Retrieval devices and related methods of use

ABSTRACT

A retrieval device may include a sheath including a distal end and a proximal end, and an end effector at the distal end. At least a portion of the end effector may be movable relative to the sheath between extended and retracted states. The end effector may include a support member extending from the distal end of the sheath, and a movable member extending from the distal end of the support member. The device may include a handle assembly at the proximal end of the sheath, having an actuation member for transitioning the end effector between the extended and retracted states. The device may include a biasing member coupled to at least one of the actuation member and the sheath that may control a force, exerted by one of the movable members and the support member on the other, generated by relative movement between the movable and support members.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims the benefits of priority from U.S. ProvisionalApplication No. 61/993,678, filed on May 15, 2014, and U.S. ProvisionalApplication No. 61/993,825, filed on May 15, 2014, each of which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

Various aspects of the present disclosure relate generally to retrievaldevices and related systems and methods. More specifically, the presentdisclosure relates to devices, systems, and methods for retrievingobjects within a patient.

BACKGROUND

Retrieval devices are often used to remove organic material (e.g., bloodclots, tissue, and biological concretions such as urinary, biliary, andpancreatic stones) and inorganic material (e.g., components of a medicaldevice or other foreign matter), which may obstruct or otherwise bepresent within a patient's body cavities or passages. For example,concretions can develop in certain parts of the body, such as in thekidneys, pancreas, ureter, and gallbladder. Minimally invasive medicalprocedures are used to remove these concretions through naturalorifices, or through an incision, such as during a percutaneousnephrolithotomy (“PNCL”) procedure. Retrieval devices are also used inlithotripsy and ureteroscopy procedures to treat urinary calculi (e.g.,kidney stones) in the ureter of a patient.

Retrieval devices may include end effectors for manipulating objects. Anexemplary end effector may have a plurality of arms that support a frontloop that forms when the end effector is opened. A user may use the armsand front loop to capture objects and/or release captured objects. Theuser's ability to capture and/or release an object may depend onfactors, including, for example, the ability of the arms and front loopto exert a grasping force on the object, the size of gaps or openingsbetween the arms, and/or the size of the front loop. Some retrievaldevices may be limited in their ability to retrieve objects due, forexample, to the size of the end effector in its extended state (e.g.,the end effector being too large or too small), and may be prone tobreakage and/or require assistance from additional devices to removelarge objects that cannot otherwise be released from the end effector.Thus, there remains a need for retrieval devices with improvedcapabilities.

The exemplary features of the present disclosure are directed toimprovements in retrieval devices and related methods of use.

SUMMARY

Aspects of the present disclosure relate to, among other things,retrieval devices and related systems and methods. Each of the aspectsdisclosed herein may include one or more of the features described inconnection with any of the other disclosed aspects.

According to aspects of the present disclosure, a device may include asheath including a distal end and a proximal end. The device may alsoinclude an end effector at the distal end of the sheath. At least aportion of the end effector may be movable relative to the sheathbetween an extended state and a retracted state. The end effector mayinclude a support member extending from the distal end of the sheath,and a movable member extending from the distal end of the supportmember. The device may also include a handle assembly at the proximalend of the sheath. The handle assembly may include an actuation memberfor transitioning the end effector between the extended state and theretracted state. The device may also include a biasing member coupled toat least one of the actuation member and the sheath. The biasing membermay control a force exerted by one of the movable member and the supportmember on the other of the movable member and the support member. Theforce may be generated by relative movement between the movable memberand the support member.

In addition or alternatively, the device may include one or more of thefeatures below. The biasing member may be movable between a rest stateand a biasing state, the biasing member being compressed or elongatedfrom the rest state to the biasing state. The biasing member may move tothe biasing state as the end effector transitions to the extended state.The biasing member may move from the biasing state to the rest state totransition the end effector to the retracted state with a predeterminedforce. The biasing member may move to the biasing state when the forcebetween the movable member and the support member is outside of apredetermined range. Movement of the biasing member to the biasing statemay be caused by relative movement between the actuation member and thesheath. The handle assembly may include a handle body slidably coupledto the actuation member. The biasing member may surround at least aportion of the sheath. The biasing member may have a proximal endfixedly coupled to the sheath, and a distal end movable relative to thesheath. The biasing member may be fixedly coupled to the actuationmember. The biasing member may have a proximal end fixedly coupled tothe sheath, and a distal end fixedly coupled to the sheath. The sheathmay include at least two sections having different degrees of stiffness.The biasing member may overlap at least a portion of each of the twosections. A connector may connect the handle assembly to the proximalend of the sheath. The connector may include a port in fluidcommunication with a lumen of the sheath for injecting a fluid into thelumen of the sheath.

According to aspects of the present disclosure, a method for operating adevice including a sheath, an end effector, a handle assembly, and abiasing member, may include transitioning the end effector from anextended state to a retracted state. The end effector may be at thedistal end of the sheath, and the end effector may include a supportmember extending from the distal end of the sheath, and a movable memberextending from the distal end of the support member. The method may alsoinclude actuating an actuation member on the handle assembly at theproximal end of the sheath to transition the end effector from theextended state to the retracted state. The method may also includecontrolling a force, exerted on one of the movable member and thesupport member by the other of the movable member and the supportmember, with the biasing member. The force may be generated by movingone of the movable member and the support member relative to the otherof the movable member and the support member. The biasing member may becoupled to at least one of the actuation member and the sheath.

In addition or alternatively, the method may include controlling theforce with the biasing member. Controlling the force may includedeforming the biasing member when the force exceeds a predeterminedrange.

According to aspects of the present disclosure, a device may include asheath including a distal end and a proximal end. The device may alsoinclude an end effector at the distal end of the sheath. The endeffector may include a plurality of support arms and a plurality ofmovable members extending from the support arms. The end effector may bemovable between an extended state and a retracted state via relativemovement between the plurality of support arms and the plurality ofmovable members. The device may also include a handle assembly includinga first actuator operatively coupled to the sheath to provide relativemovement between the plurality of movable members and distal ends of theplurality of support arms. The handle assembly may also include a secondactuator operatively coupled to the sheath to provide relative movementbetween the plurality of movable members and distal ends of theplurality of support arms. The device may also include a biasing memberoperatively coupled between the first actuator and the second actuator.The biasing member may be configured to deform to facilitate movement ofthe end effector from at least one of the extended state to a furtherextended state, and the retracted state to a further retracted state.

In addition or alternatively, the device may include one or more of thefeatures below. The biasing member may provide a lost motion connectionbetween the first actuator and the second actuator. The first actuatormay be configured to move in a distal direction relative to a handlebody to move the sheath and transition the end effector to the retractedstate. The first actuator may be configured to transfer a force to thebiasing member when the first actuator moves in the distal direction.The biasing member may be configured to deform due to the force when theforce on the first actuator exceeds a predetermined value. The firstactuator may be configured to move in a proximal direction relative tothe handle body to move the sheath and transition the end effector tothe extended state. The second actuator may be configured to transfer aforce to deform the biasing member when the second actuator moves in theproximal direction.

It may be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive of the claimed features.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary aspects of the presentdisclosure and together with the description, serve to explain theprinciples of the disclosure.

FIG. 1A is a cross-sectional side view of a portion of a retrievaldevice, in accordance with aspects of the present disclosure.

FIG. 1B is a perspective view of a portion of a retrieval device, inaccordance with aspects of the present disclosure.

FIG. 1C is another cross-sectional side view of the portion of theretrieval device of FIG. 1A, in accordance with aspects of the presentdisclosure.

FIG. 1D is another perspective view of the portion of the retrievaldevice of FIG. 1B, in accordance with aspects of the present disclosure.

FIG. 2A is a perspective view of a portion of another retrieval device,in accordance with aspects of the present disclosure.

FIG. 2B is another perspective view of the portion of the retrievaldevice of FIG. 2A, in accordance with aspects of the present disclosure.

FIG. 3A is a cross-sectional side view of a portion of a retrievaldevice, in accordance with aspects of the present disclosure.

FIG. 3B is another cross-sectional side view of the portion of theretrieval device of FIG. 3A, in accordance with aspects of the presentdisclosure.

FIG. 4A is a perspective view of a portion of a retrieval device, inaccordance with aspects of the present disclosure.

FIG. 4B is another perspective view of the portion of the retrievaldevice of FIG. 4A, in accordance with aspects of the present disclosure.

FIG. 5A is a side view of a portion of a retrieval device, in accordancewith aspects of the present disclosure.

FIG. 5B is a perspective view of a component of the portion of theretrieval device of FIG. 5A, in accordance with aspects of the presentdisclosure.

FIG. 6A is a perspective view of a portion of a retrieval device, inaccordance with aspects of the present disclosure.

FIG. 6B is a perspective view of a component of the portion of theretrieval device of FIG. 6A, in accordance with aspects of the presentdisclosure.

FIG. 7 is a side view of a portion of a retrieval device, in accordancewith aspects of the present disclosure.

FIG. 8 is a side view of a portion of a retrieval device, in accordancewith aspects of the present disclosure.

FIG. 9 is a perspective view of a portion of a retrieval device in anextended state, in accordance with aspects of the present disclosure.

FIG. 10 is a perspective view of a distal end portion of the retrievaldevice of FIG. 9 in an extended state, in accordance with aspects of thepresent disclosure.

FIG. 11 is a perspective view of a distal end portion of the retrievaldevice of FIG. 9 in a retracted state, in accordance with aspects of thepresent disclosure.

FIG. 12 is an exploded perspective view of portions of the retrievaldevice of FIG. 9, in accordance with aspects of the present disclosure.

FIG. 13 is a partial cross-sectional side view of portions of theretrieval device of FIG. 9 in an extended state, in accordance withaspects of the present disclosure.

FIG. 14 is a partial cross-sectional side view of portions of theretrieval device of FIG. 9 in a further extended state, in accordancewith aspects of the present disclosure.

FIG. 15 is a partial cross-sectional side view of portions of theretrieval device of FIG. 9, in a retracted state, in accordance withaspects of the present disclosure.

FIG. 16 is a partial cross-sectional side view of a portion of aretrieval device of FIG. 9 in a further retracted state, in accordancewith aspects of the present disclosure.

FIG. 17 is front view of a first actuator of the retrieval device alonglines 17-17 of FIG. 12, in accordance with aspects of the presentdisclosure.

FIG. 18 is a partial cross-sectional side view of a portion of aretrieval device in an extended state, in accordance with aspects of thepresent disclosure.

FIG. 19 is a partial cross-sectional side view of a portion of theretrieval device of FIG. 18 in in a further extended state, inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to aspects of the presentdisclosure, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts. The term“distal” refers to a portion farthest away from a user when introducinga device into a patient. By contrast, the term “proximal” refers to aportion closest to the user when placing the device into the patient.

FIGS. 1A-1D show portions of a retrieval device 100. Retrieval device100 may include a sheath 102 including a distal end and a proximal end.Retrieval device 100 may also include an end effector 142 at the distalend of sheath 102. At least a portion of end effector 142 may be movablerelative to sheath 102 between an extended state and a retracted state.End effector 142 may include a support member 130 coupled to the distalend of sheath 102 and a movable member 106 extending from support member130. Retrieval device 100 may also include a handle assembly 144 at theproximal end of sheath 102. Handle assembly 144 may include an actuationmember 146 for moving end effector 142 between the extended state andthe retracted state. Retrieval device 100 may also include a biasingmember 176 coupled to at least one of actuation member 146 and sheath102. Biasing member 176 may control a force exerted by one of movablemember 106 and support member 130 on the other of movable member 106 andsupport member 130, due to relative movement between movable member 106and support member 130.

Sheath 102 may be an outer sheath. Outer sheath 102 may include alongitudinally-extending lumen 136. Outer sheath 102 may be, forexample, a hollow tube. Outer sheath 102 may be made of a polymermaterial, metal, or a combination of materials.

Retrieval device 100 may also include a shaft or drive member 104. Drivemember 104 may extend through lumen 136 of outer sheath 102. Drivemember 104 may be elongated, and may include, for example, a wire,braid, shaft, and or any other suitable drive member configured totransfer translational and/or rotational forces from its proximal end toits distal end.

Retrieval device 100 may also include first, second, and third movablemembers 106, 108, and 110. Each of first, second, and third movablemembers 106, 108, and 110 may include a first proximal portion 112, 114,and 116, an intermediate portion including a reverse, U-shaped, or 180degree bend 118, 120, and 122, and a second proximal portion 124, 126,and 128. While three movable members are shown, one or more additionalmovable members may also be included. It is also contemplated that fewerthan three movable members may be included.

Each of movable members 106, 108, and 110 may be formed of any suitablematerial including, but not limited to, metals, polymers, or acombination of materials. For example, one or more of movable members106, 108, and 110 may be formed with a shape memory material, such asNitinol, and may be treated to possess an internal bias causing one ormore of movable members 106, 108, and 110 to move radially outwardlyaway from the longitudinal axis of outer sheath 102 in the absence of aconstraining force.

Each of movable members 106, 108, and 110 may have any suitablecross-sectional shape, including cylindrical, elliptical, polygonal,and/or irregular. One or more of movable members 106, 108, and 110 mayinclude a portion flattened, machined, extruded, drawn, and/or etchedinto a different profile than a remaining portion. One or more ofmovable members 106, 108, and 110 may be slotted to allow deflection ordirectional bending. Exterior surfaces of one or more of movable members106, 108, and 110 may be roughened, notched, slotted, etched,sand-blasted, or otherwise modified to provide a better grippingsurface.

Movable members 106, 108, and 110 may be attached to drive member 104.For example, proximal ends of movable members 106, 108, and 110 may beattached to the distal end of drive member 104. The attachment may beprovided by one or more of a splice joint, adhesives, melting, welding,crimping, joining using a heat shrinkable sleeve, and/or any othersuitable attachment mechanism.

Retrieval device 100 may also include first, second, and third supportmembers 130, 132, and 134. Each of support members 130, 132, and 134 mayinclude a lumen (not shown) extending longitudinally therethrough. Forexample, one or more of support members 130, 132, and 134 may be ahollow tube. Support members 130, 132, and 134 may be disposedcircumferentially about the longitudinal axis of outer sheath 102.Longitudinal axes of support members 130, 132, and 134 may be disposedat equal intervals circumferentially about the longitudinal axis ofouter sheath 102. It should, however, be noted that any other suitablenumber of support members and spacing configurations may alternativelybe utilized.

Each of support members 130, 132, and 134 may have any suitablecross-sectional shape, including cylindrical elliptical, polygonal,and/or irregular. One or more of support members 130, 132, and 134 mayinclude a portion flattened, machined, extruded, drawn, and/or etchedinto a different profile than a remaining portion. Support members 130,132, and 134 may be made of a flexible material, so that they can bendwhen being inserted into and through tortuous passages in a subject'sanatomy. One or more of support members 130, 132, and 134 may be slottedto allow deflection or directional bending. Exterior surfaces of one ormore of support members 130, 132, and 134 may be roughened, notched,slotted, etched, sand-blasted, or otherwise modified to provide a bettergripping surface. Support members 130, 132, and 134 may be made of anysuitable material, including a polymer such as polyimide, orpolyethylene terephthalate.

Proximal portions of support members 130, 132, and 134 may be receivedin lumen 136 of outer sheath 102. For example, proximal portions of oneor more of support members 130, 132, and 134 may be covered by a distalportion of outer sheath 102, leaving a distal length exposed from thedistal end of outer sheath 102. Proximal portions of support members130, 132, and 134 may be fixed relative to outer sheath 102. Forexample, the distal end of outer sheath 102 may include a coupler 138for holding support members 130, 132, and 134. Coupler 138 may include aheat-shrinkable sleeve and/or adhesive, such as an ultraviolet lightcurable adhesive or cyanoacrylate. Coupler 138 may keep the proximalends of support members 130, 132, and 134 stationary relative to thedistal end of outer sheath 102, while allowing distal portions of thesupport members 130, 132, and 134 to move relative to the distal end ofouter sheath 102 and relative to one another.

Each of support members 130, 132, and 134 may contact the other twosupport members. For example, each of the proximal portions of thesupport members 130, 132, and 134 may contact the proximal portions ofthe other two support members, such that support members 130, 132, and134 may have a triangular arrangement around the longitudinal axis ofouter sheath 102. Longitudinal axes of support members 130, 132, and 134may form vertices of a triangle, and portions of the longitudinal axesmay be parallel. Distal portions of support members 130, 132, and 134may be movable towards and away from the longitudinal axis of outersheath 102. The number of support members 130, 132, and 134 may be equalto the number of movable members 106, 108, and 110. It is contemplatedthat the number of support members and movable members may vary based onthe type of procedure being performed.

Each of movable members 106, 108, and 110 may extend distally from drivemember 104, and may enter a lumen of one of support members 130, 132,and 134 at its proximal end. Each of movable members 106, 108, and 110may extend distally through the lumen, and may exit the lumen at thedistal end of one of support members 130, 132, and 134. There each ofmovable members 106, 108, and 110 may transition into bend 118, 120, and122, respectively. Each of movable members 106, 108, and 110 may thenenter the lumen through the distal end of another one of support members130, 132, and 134. Each of movable members 106, 108, and 110 may extendproximally through the lumen, and may exit the lumen at the proximal endof one of support members 130, 132, and 134. After exiting, each ofmovable members 106, 108, and 110 may be received by a coupler 140. Forexample, coupler 140 may be positioned distally of the distal end ofdrive member 104. Coupler 140 may be a tube, and may include a lumen(not shown) configured to receive movable members 106, 108, and 110.Movable members 106, 108, and 110 may be attached to coupler 140 byadhesive, melting, welding, friction fit, heat-shrinking coupler 140,and/or any other suitable form of attachment. Coupler 140 may be fixedin place relative to the distal end of drive member 104 or may beconfigured to translate such that the position of coupler 140 changesrelative to the distal ends of support members 130, 132, and 134.

Portions of movable members 106, 108, and 110 extending distally fromdrive member 104 may extend alongside surfaces of coupler 140, and maycontact the side surfaces of coupler 140. Coupler 140 may space thoseportions of movable members 106, 108, and 110 apart from thelongitudinal axis of outer sheath 102, to help guide movable members106, 108, and 110 into the lumens of support members 130, 132, and 134.Coupler 140 may contain grooves, slots, or other recessed features toaccommodate portions of movable members 106, 108, and 110. Movablemembers 106, 108, and 110 may extend alongside and/or contacts surfacesof coupler 140 in a longitudinal, helical, wound, twisted, or othersuitable orientation.

Movable members 106, 108, and 110, and support members 130, 132, and134, may form capture members of end effector 142. End effector 142 mayform a basket. In FIG. 1B, end effector 142 is shown in a retracted andcontracted state. End effector 142 may be moved into its retracted andcontracted state by moving drive member 104 proximally relative to outersheath 102. In the retracted and contracted state, bends 118, 120, and122 may be at or adjacent to distal ends of support members 130, 132,and 134. Longitudinal axes of support members 130, 132, and 134 may besubstantially parallel, and both proximal and distal portions of each ofsupport members 130, 132, and 134 may be in contact with the othersupport members. Portions of movable members 106, 108, and 110 in thelumens of support members 130, 132, and 134 may be substantiallyparallel. Support members 130, 132, and 134, and/or outer sheath 102 maycounteract the inherent bias in movable members 106, 108, and 110,keeping portions of movable members 106, 108, and 110 from bendingradially outwardly from the longitudinal axis of outer sheath 102.

In the retracted and contracted state, the distal end of coupler 140 maybe spaced from proximal ends of support members 130, 132, and 134 by adistance. That distance may be about 12 millimeters, although otherdistances may also be used. The proximal end of coupler 140 may bespaced from the distal end of drive member 104 by a distance. Thatdistance may be about 16 millimeters, although other distances may alsobe used. The two distances may vary based on the procedure beingperformed with retrieval device 100.

In FIG. 1D, end effector 142 is shown in an extended and expanded state.In the extended and expanded state, portions of movable members 106,108, and 110 may be exposed from the distal ends of the support members130, 132, and 134. Once exposed, movable members 106, 108, and 110 maymove radially outwardly from the longitudinal axis of outer sheath 102due to inherent radially outward biasing in movable members 106, 108,and 110. Radially outward movement of movable members 106, 108, and 110may cause a radially outward movement of support members 130, 132, and134. Alternatively, support members 130, 132, and 134 may be biasedradially outwardly, and movable members 106, 108, and 110 may urgesupport members 130, 132, and 134 into the retracted and contractedstate.

In the extended and expanded state of end effector 142, exposed portionsof movable members 106, 108, and 110 may form bridges between the distalends of support members 130, 132, and 134. Each bridge may extenddistally from the distal end of a given support member, and may bereceived in the distal end of an adjacent support member. Each bridgeand its corresponding pair of support members may form a side loop ofend effector 142. Three side loops are shown in FIG. 1D. The bridges mayform a front loop of end effector 142. Materials may enter end effector142 through one or more of the front loop and the side loops. By addingadditional movable members and support members, additional side loopscan be created. It is also contemplated that end effector 142 mayinclude fewer movable members and support members. For example, endeffector 142 may include two movable members and two support members.The bridges defined by the two movable members may form a front loop.

Outer sheath 102 and support members 130, 132, and 134 may be movedproximally relative to movable members 106, 108, and 110 to extend endeffector 142, allowing end effector 142 to move to its extended andexpanded state. Drive member 104 may be moved distally relative to outersheath 102 to extend end effector 142, allowing end effector 142 to moveto its extended and expanded state. The expansion may be due to inherentradially outward biasing in one or more of movable members 106, 108, and110.

Extension and expansion of end effector 142 may occur in phases.Starting from the retracted and contracted state shown in FIG. 1B, afirst phase of the extension and expansion of end effector 142 may beginwith movement of drive member 104 distally relative to outer sheath 102and support members 130, 132, and 134. The relative movement of drivemember 104 may cause movable members 106, 108, and 110 and coupler 140to move distally relative to outer sheath 102. The movement of drivemember 104, movable members 106, 108, and 100, and coupler 140 may betranslational. First proximal portions 112, 114, and 116, and secondproximal portions 124, 126, and 128 may enter the lumens of supportmembers 130, 132, and 134 through proximal openings (not shown) insupport members 130, 132, and 134. Bends 118, 120, and 122 may emergefrom, or extend further out from, distal ends of support members 130,132, and 134.

Coupler 140 may move with movable members 106, 108, and 110 relative toouter sheath 102 and support members 130, 132, and 134. When coupler 140has traveled a distance toward proximal ends of support members 130,132, and 134, the distance being substantially equal to the distancebetween the distal end of coupler 140 and the proximal ends of supportmembers 130, 132, and 134 in FIG. 1B, further proximal movement ofcoupler 140 may be halted as coupler 140 reaches a point where itprevents further spreading of second proximal portions 124, 126, and128, thus preventing second proximal portions 124, 126, and 128 fromentering the lumens of support members 130, 132, and 134. At the end ofthe first phase of extension and expansion, bends 118, 120, and 122 maybe spaced from distal ends of support members 130, 132, and 134 by adistance substantially equal to the distance between proximal ends ofsupport members 130, 132, and 134 and the distal end of coupler 140 inFIG. 1B.

A second phase of extension and expansion of end effector 142 may beginafter distal movement of coupler 140 has been halted. During the secondphase, further distal movement of drive member 104 relative to outersheath 102 and support members 130, 132, and 134 may drive distalmovement of first proximal portions 112, 114, and 116 relative to outersheath 102 and support members 130, 132, and 134. During the secondphase, second proximal portions 124, 126, and 128 may remain fixedrelative to support members 130, 132, and 134. First proximal portions112, 114, and 116 may enter lumens in support members 130, 132, and 134via proximal openings (not shown) in support members 130, 132, and 134,and may exit the lumens via distal openings (not shown), therebyincreasing the lengths of the bridges of end effector 142, and expandingthe sizes of front and side loops of end effector 142. The second phaseof extension and expansion may continue over a distance substantiallyequal to the distance between the proximal end of coupler 140, and anintermediate position between the proximal end of coupler 140 and thedistal end of drive member 104 in FIG. 1B. Distal movement of drivemember 104 may be halted where the distal end of drive member 104prevents first proximal portions 112, 114, and 116 from spreading farenough apart to enter the proximal ends of support members 130, 132, and134. Additionally or alternatively, distal movement may be halted due tocoupler 140 obstructing further distal movement of first proximalportions 112, 114, and 116 and/or drive member 104. Additionally oralternatively, distal movement may halt due to operation of a handleassembly of retrieval device 100, such as handle assembly 144 describedfurther below.

Moving end effector 142 back to the retracted and contracted state maybe accomplished by moving outer sheath 102 and support members 130, 132,and 134 distally relative to movable members 106, 108, and 110. Movementfrom the extended and expanded state to the retracted and contractedstate may also occur in phases. A first phase of the retraction andcontraction of end effector 142 may begin with drive member 104 movingproximally relative to the outer sheath 102. This may cause firstproximal portions 112, 114, and 116 to move proximally relative to outersheath 102 and support members 130, 132, and 134. Distal portions ofmovable members 106, 108, and 110 may enter lumens at the distal ends ofsupport members 130, 132, and 134. Second proximal portions 124, 126,and 128, and coupler 140 may remain stationary relative to supportmembers 130, 132, and 134. The lengths of the bridges of end effector142 may decrease. Movable members 106, 108, and 110, and support members130, 132, and 134 may move radially inwardly. Thus, the front loop andthe side loops of end effector 142 may decrease in size.

The first phase of the retraction and contraction of end effector 142may take place over a distance substantially equal to the distancebetween a proximal end of coupler 140, and an intermediate positionbetween the proximal end of coupler 140 and the distal end of drivemember 104, in FIG. 1B. Once that distance has been covered, a secondphase of the retraction and contraction may take place with continuedmovement of drive member 104 proximally relative to outer sheath 102 andsupport members 130, 132, and 134. The continued movement may causemovable members 106, 108, and 110 and coupler 140 to move distallyrelative to outer sheath 102 and support members 130, 132, and 134. Themovement of drive member 104, movable members 106, 108, and 110, andcoupler 140 may be translational. For example, drive member 104, firstproximal portions 112, 114, and 116, second proximal portions 124, 126,and 128, and coupler 140, may move proximally relative to outer sheath102 and support members 130, 132, and 134 during the second phase.Proximal parts of first proximal portions 112, 114, and 116, and secondproximal portions 124, 126, and 128, may exit the lumens of supportmembers 130, 132, and 134 at proximal ends of support members 130, 132,and 134. Distal portions of movable members 106, 108, and 110, includingparts at or near both sides of bends 118, 120, and 122, may enter into,or move further past, the distal ends of support members 130, 132, and134. The lengths of the bridges may decrease as the exposed lengths ofmovable members 106, 108, and 110 decrease. As the bridges of endeffector 142 shrink, movable members 106, 108, and 110 and supportmembers 130, 132, and 134, may contract radially inwardly toward thelongitudinal axis of outer sheath 102. The front loop and side loops ofend effector 142 may also shrink in size.

Coupler 140 may move with movable members 106, 108, and 110 relative toouter sheath 102 and support members 130, 132, and 134. When coupler 140has traveled a distance relative to outer sheath 102 and support members130, 132, and 134, the distance being substantially equal to thedistance between proximal ends of support members 130, 132, and 134 andthe distal end of coupler 140 in FIG. 1B, further proximal movement ofcoupler 140 may be halted as bends 118, 120, and 122 reach a point wherethey prevent further proximal movement of movable members 106, 108, and110 as they engage distal ends of support members 130, 132, and 134.Additionally or alternatively, further movement may be halted byoperation of handle assembly 144. At the end of the second phase ofretraction and contraction, the state shown in FIG. 1B is attained.

FIGS. 1A and 1C show handle assembly 144. Handle assembly 144 mayinclude actuation member 146. Actuation member 146 may have a protrusion148 on its upper surface, on which the user may exert forces onactuation member 146 using his or her thumb. Actuation member 146 may becoupled to a proximal portion of outer sheath 102 by a connector 150,which may include a male luer fitting. Drive member 104 may extendproximally through a lumen 152 in connector 150, and a passage 154 inactuation member 146. A strain relief member 156 may be coupled toconnector 150, and may extend at least partially over the proximalportion of outer sheath 102. Outer sheath 102 may be moved distallyrelative to drive member 104 by moving actuation member 146 distally,and proximally by moving actuation member 146 proximally.

Actuation member 146 may slidably engage a handle body 158. For example,actuation member 146 may rest on handle body 158, and may slide distallyand proximally relative to handle body 158. Handle body 158 may befixedly coupled to a handle cover 160. Thus, actuation member 146 mayalso slide distally and proximally relative to handle cover 160. Aproximal portion of drive member 104 may extend through alongitudinally-extending passage 162 in handle body 158. At its proximalend, handle body 158 may form a vise 164, or any other suitable holdingmechanism. When vise 164 closes, handle body 158 and drive member 104may be fixedly coupled. An end cap 166 may be placed onto proximal endsof handle body 158 and handle cover 160, to help close the vise arounddrive member 104. Handle cover 160 may include an externally threadedportion (not shown), and end cap 166 may include complementary internalthreading (not shown), so end cap 166 may be screwed onto handle cover160.

When actuation member 146 is moved distally relative to handle body 158and handle cover 160, outer sheath 102 and support members 130, 132, and134 may move distally relative to drive member 104 and movable members106, 108, and 110. The distally moving support members 130, 132, and 134may slide over portions of movable members 106, 108, and 110, puttingend effector 142 in its retracted and contracted state.

A stroke limiter 168 may be coupled to a stop or abutment 172 onactuation member 146, such that stroke limiter 168 may move withactuation member 146. Alternatively, stroke limiter 168 may be coupledto a distal stop or abutment 170 on handle body 158, such that actuationmember 146 may move relative to stroke limiter 168. Stroke limiter 168may, for example, be coupled by snap-fit engagement to a recess inhandle body 158 or actuation member 146. As actuation member 146 movesdistally relative to handle body 158 and handle cover 160, the distancebetween stops 170 and 172 may decrease, as well as the distance betweendistal ends of support members 130, 132, and 134, and bends 118, 120,and 122 of movable members 106, 108, and 110. Once the distal ends ofsupport members 130, 132, and 134 move far enough distally to reachbends 118, 120, and 122, further distal movement may force supportmembers 130, 132, and 134 against bends 118, 120, and 122. If that forceis strong enough, bends 118, 120, and 122 may damage support members130, 132, and 134 by, for example, tearing into the distal ends ofsupport members 130, 132, and 134. Stroke limiter 168 may prevent suchdamage by engaging stops 170 and 172, thus limiting distal movement ofactuation member 146 relative to handle body 158 and handle cover 160,and thereby limiting distal movement of support members 130, 132, and134 relative to bends 118, 120, and 122 of movable members 106, 108, and110.

Handle body 158 may also include a stop or abutment 174, for engagingstop 172 of actuation member 146 to limit proximal travel of actuationmember 146 relative to handle body 158, thereby limiting proximalmovement of support members 130, 132, and 134 relative to movablemembers 106, 108, and 110. As actuation member 146 moves proximallyrelative to handle body 158 and handle cover 160, the distance betweenstops 172 and 174 may decrease, as well as the distance between proximalends of support members 130, 132, and 134 and coupler 140, and/orbetween proximal ends of support members 130, 132, and 134 and portionsof movable members 106, 108, and 110 leading to coupler 140.

Once the proximal ends of support members 130, 132, and 134 move farenough proximally to reach full extension and expansion of end effector142, further proximal movement may be unnecessary and/or may forcesupport members 130, 132, and 134 against coupler 140 and/or portions ofmovable members 106, 108, and 110 leading to coupler 140. If that forceis strong enough, coupler 140 and/or portions of movable member 106,108, and 110 may damage support members 130, 132, and 134 by, forexample, tearing into the proximal ends of support members 130, 132, and134. Stops 172 and 174 may prevent such damage by engaging one anotherto limit excess proximal movement of actuation member 146 relative tohandle body 158 and handle cover 160, thereby limiting proximal movementof support members 130, 132, and 134 relative to coupler 140 and/orportions of movable members 106, 108, and 110.

A biasing member 176 may be operatively coupled to actuation member 146and handle body 158. For example, biasing member 176 may surround atleast a portion of drive member 104. A distal end of biasing member 176may engage actuation member 146. In one arrangement, the distal end ofbiasing member 176 may engage a wall 178 of actuation member 146. Aproximal end of biasing member 176 may engage handle body 158. Theproximal end of biasing member 176 may engage a distal end of handlebody 158, a distal end of a sleeve 180 around drive member 104 that isreceived in passage 162 of handle body 158, and/or a portion of handlecover 160.

Biasing member 176 may exert a force biasing actuation member 146distally relative to handle body 158 and handle cover 160. Biasingmember 176 may tend to force actuation member 146 distally relative tohandle body 158 and handle cover 160 until stops 170 and 172 are forcedagainst ends of stroke limiter 168. As such, biasing member 176 may tendto force end effector 142 into its retracted and contracted state,preventing inadvertent extension and expansion of end effector 142.

It is contemplated that biasing member 176 may be supported around drivemember 104 by a flared tube or other suitable sleeve (not shown) betweenthe outer surface of drive member 104 and the internal diameter ofbiasing member 176. Alternatively, biasing member 176 may include a coiltension spring (not shown) whose ends may be coupled to stops 170 and172. Wire forming the tension spring may have a flat, round, or anyother suitable cross-sectional shape. Biasing member 176 may be made ofstainless steel, spring steel, or any other suitable material.Alternatively, biasing member 176 may include an elastic tube made ofsilicone or rubber.

Biasing member 176 is shown in a rest state in FIG. 1A, and in a biasingstate in FIG. 1C. In use, a user may overcome the biasing force ofbiasing member 176 by forcing actuation member 146 proximally relativeto handle body 158 and handle cover 160 (FIG. 1C). The user may do sowhen seeking to extend and expand end effector 142 to capture an object182 (FIG. 1D), such as a stone. If the user then attempts to close endeffector 142 around object 182 by forcing actuation member 146 distallyrelative to handle body 158 and handle cover 160, support members 130,132, and 134 may be forced distally relative to movable members 106,108, and 110, bringing movable members 106, 108, and 110 radiallyinward. Movable members 106, 108, and 110 may at some point engage theouter surface of object 182. If the user continues to force actuationmember 146 distally, support members 130, 132, and 134 may continue tomove distally. If object 182 prevents movable members 106, 108, and 110from moving radially inward as support members 130, 132, and 134 movedistally, the distal movement of support members 130, 132, and 134 maybring one or more of movable members 106, 108, and 110 against one ormore of support members 130, 132, and 134 with a greater amount of forcethan support members 130, 132, and 134 can withstand. If this happens,the distal ends of one or more of support members 130, 132, and 134 maytear, break, flare or suffer other damage.

Biasing member 176 may reduce the likelihood of damaging one or more ofsupport members 130, 132, and 134 through excessive forceful engagementwith one or more of movable members 106, 108, and 110. Biasing member176 may also reduce the likelihood of object 182 escaping from endeffector 142 due to insufficient closing force being applied to endeffector 142.

For example, once the user has extended and expanded end effector 142 tocapture object 182, the user may let go of actuation member 146 insteadof actively pushing actuation member 146 distally. Biasing member 176may move actuation member 146 distally with a predetermined force, thusclosing end effector 142 around object 182 with a predetermined closingforce. When object 182 prevents movable members 106, 108, and 110 frommoving radially inwardly any further, distal movement of actuationmember 146, and of support members 130, 132, and 134, may cease.

The predetermined closing force exerted by biasing member 176 may limitthe amount of force applied to end effector 142, and in particular, tosupport members 130, 132, and 134 by movable members 106, 108, and 110.The predetermined closing force may be selected to ensure that theforces between movable members 106, 108, and 110 and support members130, 132, and 134 are limited such that movable members 106, 108, and110 will not damage support members 130, 132, and 134. If an additionalamount of closing force is required, the user may remove end cap 166,grasp the proximal end of drive member 104, and pull drive member 104distally relative to actuation member 146. Additionally oralternatively, the user may exert more closing force by pushingactuation member 146 distally to supplement the biasing force exerted bybiasing member 176. Stroke limiter 168 will eventually prohibit furthermovement of actuation member 146 distally when end effector 142 reachesthe fully retracted and contracted state.

FIGS. 2A and 2B show movable or capture members 208 and 210 that arealternatives of movable members 108 and 110 (FIGS. 1A-1D). Movablemembers 208 and 210 may not be coupled to drive member 104. Rather,movable members 208 and 210 may include proximal portions 226 and 228,respectively, coupled on their proximal ends to coupler 140. Movablemembers 208 and 210 may also include opposite ends fixed within supportmember 134. Those ends may be fixed within support member 134 by anysuitable attachment mechanism. For example, the ends may be fixed withinsupport member 134 by an adhesive, support member 134 may be crimpedaround the ends, and/or support member 134 may be heat shrunk onto theends.

Between their ends, movable members 208 and 210 may include reverse,U-shaped, or 180 degree bends 220 and 222, respectively. Proximalportion 226 of movable member 208 may be slidable into and out ofsupport member 132, and proximal portion 228 of movable member 210 maybe slidable into and out of support member 130. The portions of movablemembers 208 and 210 on the other sides of their respective bends 220 and222, extending through and fixedly coupled to support member 134, mayremain fixed relative to support member 134.

FIG. 2A shows movable members 118, 208, and 210, and support members130, 132, and 134 in a retracted and contracted state. From that state,moving outer sheath 102 and support members 130, 132, and 134 proximallyrelative to drive member 104 and movable member 106, may expose portionsof movable member 106 from distal ends of support members 130 and 132.The inherent bias in movable member 106 may cause support members 130and 132 to expand radially outwardly from the longitudinal axis of outersheath 102. Portions of movable members 208 and 210 in support members130 and 132 may be exposed during the radially outward movement ofsupport members 130 and 132.

Support member 134, however, may remain substantially stationary. Theinherent bias in movable member 106, while being capable of deflectingsupport members 130 and 132, may be insufficient for deflecting supportmember 134. Support member 134 may act as a stationary point and/orguide for positioning against object 182. Support member 134 may helpkeep object 182 substantially stationary during closing of movablemembers 208 and 210 and support members 130 and 132 around object 182.If support member 134 does not remain substantially stationary duringclosing, one or more of movable members 106, 208, and 210 and/or supportmembers 130, 132, and 134 may potentially engage object 182 beforeanother of movable members 106, 208, and 210 and/or support members 130,132, and 134, causing object 182 to move. If object 182 is small enoughrelative to the openings defined by movable members 106, 208, and 210and/or support members 130, 132, and 134, object 182 may escape throughone of those openings. By keeping support member 134 substantiallystationary, the likelihood of losing object 182 may be reduced, sincesupport member 134 may help keep object 182 relatively still duringclosing. Further the lack of movement of support member 134 may helplimit the size of front and side openings defined by movable members106, 208, and 210 and/or support members 130, 132, and 134, providingadditional assistance with respect to retrieving small objects.

It is contemplated that support member 134 may have a visual featurethat distinguishes it from support members 130 and 132, to help the useridentify the support member that will remain substantially stationaryduring opening and closing. For example, support member 134 may have adifferent color than support members 130 and 132. It should beunderstood that while support member 134 may remain substantiallystationary during opening and closing, support member 134 may be asflexible as support members 130 and 132. For example, all three supportmembers 130, 132, and 134 may be made of the same or similar materials.

FIG. 3A shows a connector 350 that is an alternative of connector 150(FIGS. 1A and 1C). Connector 350 may be a male luer fitting. Connector350 may be fixedly coupled to a distal portion of actuation member 146.Connector 350 may include a lumen 352 in which a portion of drive member104 may be received. Lumen 352 may be in fluid communication with lumen136 of outer sheath 102. Connector 350 may include a port 384 with alumen 386 having an inlet 388. Lumen 386 may be in fluid communicationwith lumen 352 of connector 350. A fluid (not shown) may be introducedinto lumen 386 via inlet 388. It is contemplated that inlet 388 mayinclude a valve or seal (not shown) for limiting or preventing leakageof the fluid from inlet 388. The fluid may travel through lumen 386 intolumen 352. It is contemplated that a valve or seal (not shown) may beprovided around drive member 104 at a position proximal to lumen 386 tolimit or prevent fluid flow proximally out of the proximal end of lumen352.

The fluid may flow distally through lumen 352 into lumen 136 of outersheath 102. The fluid may be introduced with sufficient pressure toforce the fluid to the distal end of outer sheath 102. For example, thefluid may flow through one or more gaps between support members 130,132, and 134, and out of the distal end of outer sheath 102.Additionally or alternatively, the fluid may flow through one or more ofsupport members 130, 132, and 134, and out of the distal end of one ormore of support members 130, 132, and 134. The fluid may be emittedwhile the support members 130, 132, and 134 are retracted or collapsed,or extended and expanded. It is contemplated that one or more of supportmembers 130, 132, and 134 may include one or more openings (not shown)between their proximal and distal ends through which the fluid may besecreted.

FIG. 3B shows connector 350 with an inner tube or lumen 390 extendingthrough lumen 386. A fluid may be introduced into inner lumen 390 viainlet 388. The fluid may travel through inner lumen 390. Inner lumen 390may extend distally through lumen 352 of connector 350 and lumen 136 ofouter sheath 102. It is contemplated that inner lumen 390 may terminatein outer sheath 102 proximal of support members 130, 132, and 134. Fluidinjected into inner lumen 390 may flow into outer sheath 102 through oneor more gaps between support members 130, 132, and 134, and out of thedistal end of outer sheath 102. Additionally or alternatively, the fluidmay flow through one or more of support members 130, 132, and 134 andout of the distal end of one or more of support members 130, 132, and134.

Alternatively, inner lumen 390 may extend through a gap between supportmembers 130, 132, and 134, terminating within the gap or at the distalend of outer sheath 102. The fluid may flow through the gap and out ofouter sheath 102. It is also contemplated that inner lumen 390 mayextend distally beyond the distal end of outer sheath 102.

Alternatively, inner lumen 390 may terminate at one of support members130, 132, and 134. For example, inner lumen 390 may terminate at aproximal end, distal end, or intermediate portion of one of supportmembers 130, 132, and 134. The injected fluid may flow through innerlumen 390 into the support member, and out the distal end of the supportmember. It is also contemplated that inner lumen 390 may extend distallybeyond the distal end of the support member.

Additionally or alternatively, there may be a plurality of inner lumens(not shown), or inner lumen 390 may branch off into a plurality of innerlumens. It is contemplated that one or more of the inner lumens mayterminate in outer sheath 102 proximal of support members 130, 132, and134. Additionally or alternatively, one or more of the inner lumens mayextend through a gap between support members 130, 132, and 134.Additionally or alternatively, one or more of the inner lumens mayterminate at one or more of support members 130, 132, and 134.

The fluid may include, for example, a gel. The gel may include awater-soluble polymer that may form a plug in a subject's body. Oneexample of such a gel is BACKSTOP™ from Boston Scientific. The fluid maybe reverse thermosensitive. Thus, the fluid may be soft and easy toinject at room temperature, and more viscous at body temperature. Whenintroduced into the subject's body, the fluid may help trap smallobjects or fragments of objects. This may assist with keeping suchobjects in contact with movable members 106, 108, and 110, supportmembers 130, 132, and 134, and/or outer sheath 102. Additionally oralternatively, the fluid may trap multiple fragments and form them intoa larger mass for easier capture and handling.

In use, after a user has captured object 182 in end effector 142, theuser may perform lithotripsy on object 182 to break it apart intosmaller pieces. Prior to, during, or after performing lithotripsy, thefluid may be directed toward the area around object 182. As the fluidbecomes more viscous due to the subject's body heat, the pieces ofobject 182 may be caught and held by the fluid. Thus, end effector 142may exert more of a holding force on the pieces. When the procedure iscompleted, the fluid may be removed from device surfaces using a salinewash. The saline may, for example, be introduced through port 384 toflush the fluid out.

FIGS. 4A and 4B show an actuation member 446 and a handle body 458, thatare alternatives of actuation member 146 and handle body 158 (FIGS. 1Aand 1C), respectively. Connector 150 may be coupled to a distal end ofactuation member 446. Actuation member 446 may include sidewalls 492defining a slot 494. Handle body 458 may be slidably received in slot494 for sliding between a first position (FIG. 4A), corresponding to anend effector retracted and contracted state, and a second position (FIG.4B) corresponding to an end effector extended and expanded state. Handlebody 458 may include sidewalls 496 defining a slot 498. It iscontemplated that drive member 104 may extend proximally throughconnector 150, slot 494 of actuation member 446, and slot 498 of handlebody 458. Handle body 458 may include a proximal vise 464 for grippingdrive member 104.

FIGS. 5A and 5B show an outer sheath 502 that is an alternative of outersheath 102. A portion of outer sheath 502 may be surrounded by a biasingmember 503. Biasing member 503 may be a coil spring, such as a tensionspring. A connector 505, which may be a female luer fitting, may befixedly coupled to the portion of biasing member 503 extending throughit using, for example, gluing, insert molding, heat-shrinking, crimping,and/or any other suitable form of attachment. Biasing member 503 may bemade stainless steel, spring steel, or any other suitable material.Biasing member 503 may be made of wire having a flat, round, or anyother suitable cross-sectional shape. Alternatively, biasing member 503may include an elastic tube made of silicone or rubber.

A proximal end of connector 505 may be received by a distal end ofconnector 150. The portion of biasing member 503 distal to connector 505may help relieve strain in the portion of outer sheath 502 extendingdistally from connector 505. By relieving strain, the distal portion ofbiasing member 503 may help prevent outer sheath 502 from kinking at ornear connector 505. The portion of biasing member 503 proximal toconnector 505, along with outer sheath 502, may extend into actuationmembers 146 or 446 and handle bodies 158 or 458 (FIGS. 4A and 4B),respectively.

The proximal end of biasing member 503 may be fixedly attached to outersheath 502 using, for example, gluing, heat-shrinking, insert molding,crimping, and/or any other suitable form of attachment. Portions ofbiasing member 503 distal to the proximal end of biasing member 503 maybe movable relative to the exterior surface of outer sheath 502. Forexample, while the proximal end of biasing member 503 may be fixedlyattached to outer sheath 502, the distal end of biasing member 503 maymove distally relative to outer sheath 502 during elongation andcompression of biasing member 503. Biasing member 503 may be configuredwithout gaps between adjacent turns of biasing member 503 when in itsrest state. Once it has been elongated, biasing member 503 may be biasedto return to its rest state.

A key member 507 may be fixedly attached a proximal portion of outersheath 502. Key member 507 may overlap the proximal end of biasingmember 503, and may also be fixedly attached to the proximal end ofbiasing member 503. Key member 507 may be slidably received in a passage509 in a keyed member 511. Key member 507 may have an outer shapecomplementary to the shape of passage 509, such that torque may betransferred from keyed member 511 to key member 507.

Keyed member 511 may be received within passage 162 of handle body 158or slot 498 of handle body 458. Keyed member 511 may be fixedly coupledto handle bodies 158 or 458 by interference fit between keyed member 511and walls forming passage 162 or walls 496 forming slot 498.Additionally or alternatively, keyed member 511 may be fixedly coupledto walls forming passage 162 or walls 496 of slot 498 by adhesive, orany other suitable form of attachment.

In use, end effector 142 may be extended and expanded to capture object182 by moving actuation members 146 or 446 proximally relative to handlebodies 158 or 458. This may cause components coupled to actuationmembers 146 or 446, such as connector 150, biasing member 503, keymember 507, outer sheath 502, and support members 130, 132, and 134, tomove proximally relative to components coupled to handle bodies 158 or458, such as movable members 106, 108, and 110, drive member 104, andkeyed member 511.

Once object 182 is captured within the extended and expanded endeffector 142, end effector 142 may be retracted and contracted to closemovable members 106, 108, and 110, and/or support members 130, 132, and134, around object 182. To close end effector 142, actuation members 146or 446 may be moved distally relative to handle bodies 158 or 458. Thismay cause components coupled to actuation members 146 or 446, such asconnector 150, biasing member 503, key member 507, outer sheath 502, andsupport members 130, 132, and 134, to move distally relative tocomponents coupled to handle bodies 158 or 458, such as movable members106, 108, and 110, drive member 104, and keyed member 511.

When end effector 142 engages object 182, object 182 may obstructfurther closing of end effector 142. If the user attempts to moveactuation members 146 or 446 distally relative to handle bodies 158 or458, the force exerted by the user may overcome the rest state ofbiasing member 503. Actuation members 146 or 445, by moving connector505 that may be coupled to biasing member 503, may pull a distal portionof biasing member 503 distally, while outer sheath 502, and the proximalportion of biasing member 503 coupled to outer sheath 502, may remainrelatively static due to object 182 preventing further closure of endeffector 142 and obstructing distal movement of outer sheath 502. Assuch, biasing member 503 may elongate to accommodate that movement,allowing actuation members 146 or 446 to move further distally withoutcausing distal movement of outer sheath 502 and support members 130,132, and 134. The elongation of biasing member 503 may take upmovement/forces that would otherwise be transferred to support members130, 132, and 134 and movable members 106, 108, and 110. By taking upsuch forces, tearing, flaring, breaking, or other types of damage tosupport members 130, 132, and 134, through overly forceful contact withmovable members 106, 108, and 110, may be avoided. The forces betweensupport members 130, 132, and 134 and movable members 106, 108, and 110may be limited such that they do not exceed what support members 130,132, and 134 can withstand before tearing, flaring, breaking, orsuffering another type of damage. Biasing member 503 may begin taking upthe forces when they fall outside a predetermined range.

Alternatively, biasing member 503 may be fixedly coupled to outer sheath502 at both the proximal and distal ends of biasing member 503. Theportion of biasing member 503 distal to connector 505 may have gapsbetween its turns, and may act as a compression spring between connector505 and outer sheath 502, while the portion of biasing member 503proximal to connector 505 may act as a tension spring between connector505 and outer sheath 502. In this arrangement, if the user attempts tomove actuation members 146 or 446 distally relative to handle bodies 158or 458 when further closing of end effector 142 is limited by thepresence of object 182 therein, the compression spring portion ofbiasing member 503 may compress and/or the tension spring portion ofbiasing member 503 may elongate, allowing actuation members 146 or 446and handle bodies 158 or 458 to move distally without moving outersheath 502 and support members 130, 132, and 134 distally. Thatelongation may help prevent bringing support members 130, 132, and 134against movable members 106, 108, and 110 with enough force to causeflaring, tearing, breaking, or other damaging of support members 130,132, and 134. That is, the compression spring portion of biasing member503 and/or the tension spring portion of biasing member 503 may take upexcess closing forces/motions to prevent damage to support members 130,132, and 134. Biasing member 503 may limit forces between supportmembers 130, 132, and 134 and movable members 106, 108, and 110 so theforces remain below a tear, flare, or break strength of one or more ofsupport members 703. Biasing member 503 may begin taking up thoseforces/motions when they fall outside a predetermined range depending,at least in part, on the spring constant of biasing member 503.

In use, the user may also attempt to rotate end effector 142 about thelongitudinal axis of outer sheath 502 by rotating actuation members 146or 446, handle bodies 158 or 458, and handle cover 160 about thelongitudinal axis of outer sheath 502. The engagement between key member507 and keyed member 511 may help ensure that rotation of actuationmembers 146 or 446, handle bodies 158 or 458, and handle cover 160 aboutthe longitudinal axis of outer sheath 502 may result in rotation ofconnector 505, biasing member 503, outer sheath 502, and support members130, 132, and 134 in unison with drive member 104 and movable members106, 108, and 110.

FIGS. 6A and 6B show a torque transfer clip 611 that is an alternativeto key member 507 and keyed member 511 (FIGS. 5A and 5B). Torquetransfer clip 611 may fit by interference fit, adhesive, or any othersuitable form of attachment, into passage 162 of handle body 158 or slot498 of handle body 458. Proximal portions of biasing member 503 andouter sheath 502 may be fixedly coupled to torque transfer clip 611,within a passage 609 extending longitudinally through torque transferclip 611, by adhesive or any other suitable attachment.

FIG. 7 shows portions of other aspects of retrieval device 100.Retrieval device may include an outer sheath 702. Drive member 104 mayextend through outer sheath 702, and may be longitudinally slidableproximally and distally relative to outer sheath 702. Movable members106, 108, and 110 may be coupled to drive member 104 (FIGS. 1B and 1D).Proximal portions of support members 130, 132, and 134 may be fixedlycoupled to the distal end of outer sheath 702 by, for example, coupler138 or any other suitable form of attachment. Movable members 106, 108,and 110, and support members 130, 132, and 134, may form end effector142.

A handle assembly 744 may include an actuation member 746. Actuationmember 746 may have a protrusion 748 on its upper surface, on which theuser may exert forces on actuation member 746 using his or her thumb. Aproximal portion of sheath 702 may extend through a lumen 752 ofactuation member 746 and into a passage 754 of actuation member 746.Sheath 702 and actuation member 746 may slide proximally and distallyrelative to each other.

Drive member 104 may extend proximally through lumen 752 of actuationmember 746, and through a passage 754 in actuation member 756. Drivemember 104 may be coupled to a vise 764 on a proximal end of a handlebody 758. Handle body 758 may slidably engage actuation member 746. Forexample, handle body 758 may be slidably received within passage 754 ofactuation member 746, such that handle body 758 and actuation member 746may slide proximally and distally relative to each other. Handle body758 may be hollow. The proximal portion of sheath 702 may extend intothe hollow area of handle body 758. It is contemplated that handle body758 may be coupled to handle cover 160 and end cap 166 (FIGS. 1A and1C). Screwing end cap 166 on handle cover 160 may help close vise 764around the proximal end of drive member 104.

When actuation member 746 is moved distally from the position in FIG. 7relative to handle body 758, outer sheath 702 and support members 130,132, and 134 may move distally relative to drive member 104 and movablemembers 106, 108, and 110. The distally moving support members 130, 132,and 134 may slide over portions of movable members 106, 108, and 110,putting end effector 142 in its retracted and contracted state (FIG.1B). A stroke limiter 768 coupled to a proximal portion of actuationmember 746 may set a limit on distal movement of actuation member 746when stroke limiter 768 comes into contact with a stop or abutment 770on handle body 758. When the distal end of stroke limiter 768 contactsthe proximal end of stop 770, end effector 142 may be in its fullyretracted and contracted state.

With end effector 142 in a retracted and contracted state, actuationmember 746 may be moved proximally relative to handle body 758, causingouter sheath 702 and support members 130, 132, and 134 to moveproximally relative to drive member 104 and movable members 106, 108,and 110. Continued proximal movement of actuation member 746 may lead toincreasing exposure of movable members 106, 108, and 110 from the distalends of support members 130, 132, and 134, and extension and expansionof end effector 142 (FIG. 1D). When a stop or abutment 772 on a proximalend of actuation member 746 contacts a stop or abutment 774 on handlebody 758, end effector may be at full extension and expansion.

A biasing member 703 may couple actuation member 746 and sheath 702. Forexample, biasing member 703 may be a coil spring surrounding a portionof outer sheath 702 within handle assembly 744. Alternatively, biasingmember 703 may include an elastic tube made of silicone or rubber. Adistal end of biasing member 703 may be fixedly coupled to a wall 778 ofactuation member 746. A proximal end of biasing member 703 may befixedly coupled to a proximal end portion of sheath 702. During proximalmovement of actuation member 746 relative to handle body 758, biasingmember 703 may remain in rest state. Biasing member 703 may provide asubstantially non-moving link between actuation member 746 and outersheath 702 during extension and expansion of end effector 142.

When end effector 142 captures object 182 (FIG. 1D), the user mayattempt to close end effector 142 around object 182 by moving actuationmember 746 distally relative to handle body 758. Movable members 106,108, and 110 may at some point engage the outer surface of object 182during closing of end effector 142. Object 182 may prevent furtherclosure of end effector 142. Further movement of actuation member 746distally could bring one or more of movable members 106, 108, and 110against one or more of support members 130, 132, and 134 with sufficientforce to tear, flare, break, or otherwise damage the distal ends of oneor more of support members 130, 132, and 134.

Biasing member 703 may reduce the likelihood of damaging one or more ofsupport members 130, 132, and 134 through excessive forceful engagementwith one or more of movable members 106, 108, and 110. When end effector142 closes on object 182, and object 182 obstructs further closing ofend effector 142, further attempts by the user to move actuation member746 distally relative to handle body 758 may cause biasing member 703 toelongate. That is, wall 778 of actuation member 746 may pull the distalend of biasing member 703 distally while outer sheath 702 and theproximal end of biasing member 703 remain relatively static due toobject 182 obstructing distal movement of outer sheath 702 and supportmembers 130, 132, and 134. Elongation of biasing member 703 may allowactuation member 746 to move further distally without causing distalmovement of outer sheath 702 and support members 130, 132, and 134. Theelongation may take up movement/forces that would otherwise betransferred to support members 130, 132, and 134 and movable members106, 108, and 110. By taking up such forces, tearing, flaring, breaking,or other types of damage to support members 130, 132, and 134 throughforceful contact with movable members 106, 108, and 110, may be avoided.For example, biasing member 703 may limit forces between support members130, 132, and 134 and movable members 106, 108, and 110 so the forcesremain below a tear, flare, or break strength of one or more of supportmembers 703. Biasing member 703 may being taking up forces when theyfall outside a predetermined range. The predetermined range may depend,at least in part, on the spring constant of biasing member 703.

FIG. 8 shows an outer sheath 802 that is an alternative to outer sheaths102 and 502. At its proximal end, outer sheath 802 may be coupled toconnector 505. Connector 505 may be received by connector 150 (FIGS. 1Aand 1C). Outer sheath 802 may include sections having different degreesof stiffness. For example, outer sheath 802 may include a proximalsection 813 having a first stiffness, an intermediate section 815 havinga second stiffness, and a distal section 817 having a third stiffness.The first stiffness may be greater than the second stiffness. The thirdstiffness may also be greater than the second stiffness. The firststiffness and third stiffness may be substantially equal. The stiffnessof a section may be made higher by providing outer sheath 802 withthicker walls in that section, or lower by providing outer sheath 802with thinner walls in that section. Additionally or alternatively, thestiffness of a section may be made higher by making outer sheath 802 outof a stiffer material in that section, or lower by making outer sheath802 with a more flexible material in that section. Additionally oralternatively, the stiffness of a section may be made lower by etchingthat section.

A biasing member 819 may be applied around outer sheath 802. Biasingmember 819 may be fixedly coupled at its proximal and distal ends toouter sheath 802. For example, ends of biasing member 819 may be fixedlycoupled to proximal and distal sections 813 and 817. Biasing member 819may have gaps between adjacent turns, and may act as a compressionspring, tending to bias outer sheath 802 to its full length. Portions ofbiasing member 819 between its proximal and distal ends may slide freelyalong outer sheath 802. Biasing member 819 may include a coil springmade of stainless steel, spring steel, or any other suitable material.Wire forming the coil spring may have a flat, round, or any othersuitable cross-sectional shape. Alternatively, biasing member 819 mayinclude an elastic tube made of silicone, rubber, or any other suitablematerial.

During use, when end effector 142 has been extended and expanded aroundobject 182, object 182 may obstruct the full closing action of endeffector 142. As the user moves actuation members 146 or 446 distallyrelative to handle bodies 158 or 458, outer sheath 802 may be compresseddue to the force exerted by object 182 on its distal end, and the forceexerted by the user on its proximal end. That compressive force maycause outer sheath 802 to shorten, and may cause biasing member 819 tobe compressed. When the user stops moving actuation members 146 or 446distally, and/or when object 182 is released from end effector 142, thecompressive force on outer sheath 802 may be relieved. Biasing member819 may decompress and elongate, leading to elongation of outer sheath802 due to biasing member 819 being fixedly coupled at its proximal enddistal ends to outer sheath 802.

FIGS. 9-17 show portions of a retrieval device 1100 according to anotheraspect of this disclosure. Retrieval device 1100 may include a handleassembly 1102 at the proximal end of the device 1100, a sheath 1104, andan end effector 1106 at the distal end of the device 1100. The handleassembly 1102 may include handle body 1140 (FIG. 12), a handle cover1141, a first actuator or actuation member 1108, and a second actuatoror actuation member 1110. As shown in FIG. 12, second actuator 1110 maytake the form of a trigger assembly and may include various components,such as shaft 1112, plunger 1114, biasing member 1116, and trigger 1118.The second actuator 1110 reciprocates within the first actuator 1108.The first actuator 1108 controls a maximum retracted state of the device1100 and the second actuator 1110 controls a maximum extended state ofthe device 1100.

Referring to FIGS. 9-11, the sheath 1104 of the device 1100 may includea longitudinally-extending lumen. Sheath 1104 may be, for example, ahollow tube and may be manufactured using of any suitable material orcombination of materials. Exemplary materials may include polymers ormetals. Sheath 1104 may have any suitable features, for example, sheath1104 may have varying flexibility, therapeutic coatings, visualizationfeatures (for direct visualization and/or viewing by an imaging device),surface features (e.g. protrusions, indentations, roughened portions),shape memory properties, etc. The sheath 1104 may have any suitable sizeand shape for insertion in the body. Portions of the sheath 1104 may becovered by various materials such as coatings and/or covers havingvarious suitable properties. For example, a strain relief member 1134may be operatively coupled to the trigger assembly 1110 and may extendat least partially over a proximal portion of sheath 1104. The strainrelief member 1134 may have any suitable size and shape for extendingover sheath 1104 and decreasing distortion of sheath 1104 and may bemanufactured using any suitable materials or combination of materials.

As shown in FIGS. 10-16, the retrieval device 1100 may also include ashaft or drive member 1142, which may extend through a lumen 1148 of thesheath 1104 and the handle assembly 1102. The drive member 1142 may beelongated, and may include, for example, one or more wires, braids,shafts, etc. configured to transfer translational and/or rotationalforces from its proximal end to its distal end. Drive member 1142 may,for example, be similar to drive member 104 (FIG. 1A). As will beexplained in more detail below, the sheath 1104 may be movable relativeto the drive member 1142 to close and open portions of the end effector1106.

Referring to FIGS. 9-11, the end effector 1106 may have first, second,and third movable/capture members 1152, 1154, and 1156. While threemovable members are shown, one or more additional movable members mayalso be included. It is also contemplated that fewer than three movablemembers may also be included. Each of movable members 1152, 1154, and1156 may be manufactured using any suitable material or combination ofmaterials including, but not limited to, metals, polymers, or acombination of materials. For example, one or more of movable members1152, 1154, and 1156 may be formed with a shape memory material, such asNitinol, and may be treated to possess an internal bias causing one ormore of movable members 1152, 1154, and 1156 to move radially outwardlyaway from the longitudinal axis of sheath 1104 in the absence of aconstraining force.

Each of movable members 1152, 1154, and 1156 may have any suitablecross-sectional shape, including cylindrical, elliptical, polygonal,and/or irregular. One or more of the movable members 1152, 1154, and1156 may include a portion flattened, machined, extruded, drawn, and/oretched into a different profile than a remaining portion. One or more ofmovable members 1152, 1154, and 1156 may be slotted to allow deflectionor directional bending. Exterior surfaces of the one or more of movablemembers 1152, 1154, and 1156 may be roughened, notched, slotted, etched,sand-blasted, or otherwise modified to provide a better grippingsurface.

Movable members 1152, 1154, and 1156 may be operatively coupled to thedrive member 1142. For example, proximal ends of movable members 1152,1154, and 1156 may be fixedly attached to a distal end of the drivemember 1142 (now shown). The attachment may be provided by one or moreof a splice joint, adhesives, melting, welding, crimping, joining usinga heat shrinkable sleeve, and/or any other suitable attachment mechanismor process. Movable members 1152, 1154, and 1156 may, for example, besimilar to movable members 106, 108, and 110.

End effector 1106 also may include first, second, and third supportmembers 1158, 1160, and 1162. Each of the support members 1158, 1160,and 1162 may include a lumen (not shown) extending longitudinallytherethrough. For example, support members 1158, 1160, and 1162 may be ahollow tube. Support members 1158, 1160, and 1162 may be disposedcircumferentially about the longitudinal axis of the sheath 1104.Longitudinal axes of support members 1158, 1160, and 1162 may bedisposed at equal intervals circumferentially about the longitudinalaxis of sheath 1104. Any other suitable number of support members andspacing configurations may alternatively be utilized.

Each support member 1158, 1160, and 1162 may have any suitablecross-sectional shape, including cylindrical elliptical, polygonal,and/or irregular. One or more of support members 1158, 1160, and 1162may include a portion flattened, machined, extruded, drawn, and/oretched into a different profile than a remaining portion. Supportmembers 1158, 1160, and 1162 may be made of a flexible material, so thatthey may bend when being inserted into and through tortuous passages ina subject's anatomy. One or more of support members 1158, 1160, and 1162may be slotted to allow deflection or directional bending. Exteriorsurfaces of one or more of support members 1158, 1160, and 1162 may beroughened, notched, slotted, etched, sand-blasted, or otherwise modifiedto provide a better gripping surface. Support members 1158, 1160, and1162 may be made of any suitable material, or combination of materialssuch as polymers (e.g. polyimide, or polyethylene terephthalate), and ormetals (e.g. Nitinol), etc.

As shown in FIGS. 10 and 11, proximal portions of support members 1158,1160, and 1162 are received in a distal end of sheath 1104. For example,proximal portions of one or more of support members 1158, 1160, and 1162may be covered by a distal portion of sheath 1104, leaving a distallength exposed from the distal end of sheath 1104. Proximal portions ofsupport members 1158, 1160, and 1162 may be fixed relative to sheath1104. For example, via a sleeve or heat-shrinkable sleeve and/oradhesive, such as an ultraviolet light curable adhesive orcyanoacrylate. The proximal ends of support members 1158, 1160, and 1162may be stationary relative to the distal end of sheath 1104, whileallowing distal portions of the support members 1158, 1160, and 1162 tomove relative to the distal end of sheath 1104 and relative to oneanother between the exemplary portions shown in FIGS. 10 and 11.

Each support member 1158, 1160, and 1162 may contact the other twosupport members. For example, each of the proximal portions of thesupport members 1158, 1160, and 1162 may contact the proximal portionsof the other two support members, such that support members 1158, 1160,and 1162 may have a triangular arrangement around the longitudinal axisof sheath 1104. Longitudinal axes of support members 1158, 1160, and1162 may form vertices of a triangle, and portions of the longitudinalaxes may be parallel. Distal portions of support members 1158, 1160, and1162 may be movable towards and away from the longitudinal axis ofsheath 1104. The number of support members 1158, 1160, and 1162 may beequal to the number of movable members 1152, 1154, and 1156. It iscontemplated that the number of support members and movable members mayvary based on the type of procedure being performed. It is alsocontemplated that support member 1158, 1160, and 1162 may be similar tosupport members 130, 132, and 134.

Each of movable members 1152, 1154, and 1156 may extend distally fromdrive member 1142, and may enter a lumen of one of support members 1158,1160, and 1162 at its proximal end. Each of movable members 1152, 1154,and 1156 may extend distally through the lumen of the support member,and may exit the lumen at the distal end of one of support members 1158,1160, and 1162. Each of movable members 1152, 1154, and 1156 may thentransition into a bend and may enter a lumen through the distal end ofanother one of support members 1158, 1160, and 1162. Each of movablemembers 1152, 1154, and 1156 may then extend proximally through thelumen, and may exit the lumen at the proximal end of one of supportmembers 1158, 1160, and 1162. After exiting, each of movable members1152, 1154, and 1156 may be operatively coupled together in any fashion,such as by a clamp, adhesive, melting, welding, friction fit,heat-shrinking, and/or any other suitable form of attachment. Themovable members 1152, 1154, and 1156 are secured to allow forlongitudinal movement within all of the support members 1158, 1160, and1162. For example, during initial opening of the end effector 1106, themovable members 1152, 1154, and 1156 may all move an initial distancewithin the support members 1158, 1160, and 1162 to relieve openingforces of the device. The initial distance may be any suitablepredetermined distance that may be controlled by the placement of astop.

Portions of movable members 1152, 1154, and 1156 extending distally fromdrive member 1142 may extend alongside surfaces of a spacer to spacethose portions of movable members 1152, 1154, and 1156 apart from thelongitudinal axis of sheath 1104, to help guide movable members 1152,1154, and 1156 into the lumens of support members 1158, 1160, and 1162.

Movable members 1152, 1154, and 1156, and support members 1158, 1160,and 1162, form the end effector 1106. End effector 1106 may form abasket or grasper having front and side openings for capturing targetobjects 1300 in an open or extended state as shown in FIG. 10. In FIG.11, end effector 1106 is shown in a retracted or closed state. Endeffector 1106 may be moved into its retracted or closed state by movingfirst actuator 1108 in a distal direction indicated by arrow “C” (shownin FIG. 13) to in turn move the sheath 1104 and associated supportmembers 1158, 1160, and 1162 distally relative to the movable members1152, 1154, and 1156 and drive member 1142. Moving the support members1158, 1160, and 1162 over the movable members serves to close the endeffector 1106.

In the retracted state, bends formed in the movable members 1152, 1154,and 1156 may be at or adjacent to distal ends of support members 1158,1160, and 1162, as shown in FIG. 11. Longitudinal axes of supportmembers 1158, 1160, and 1162 may be substantially parallel in theretracted state, and both proximal and distal portions of each ofsupport members 1158, 1160, and 1162 may be in contact with the othersupport members. Portions of movable members 1152, 1154, and 1156 in thelumens of support members 1158, 1160, and 1162 may be substantiallyparallel. Support members 1158, 1160, and 1162, and/or sheath 1104 maycounteract the inherent bias in movable members 1152, 1154, and 1156,keeping portions of movable members 1152, 1154, and 1156 from bendingradially outwardly from the longitudinal axis of sheath 1104 in theretracted state.

In FIG. 13, end effector 1106 is shown in an extended state. In theextended state, portions of movable members 1152, 1154, and 1156 may beexposed from the distal ends of the support members 1158, 1160, and 1162due to withdrawal of the sheath 1104 in a proximal direction indicatedby the arrow “O”. This may be accomplished by movement of the firstactuator or actuation member 1108 in a proximal direction indicated byarrow “O” which may in turn move trigger assembly 1110 proximally tomove or withdraw the sheath 1104 and connected support members 1158,1160, and 1162 in a proximal direction. Once exposed, movable members1152, 1154, and 1156 may move radially outwardly from the longitudinalaxis of sheath 1104 due to inherent radially outward biasing in movablemembers 1152, 1154, and 1156. Radially outward movement of movablemembers 1152, 1154, and 1156 may cause a radially outward movement ofsupport members 1158, 1160, and 1162. Alternatively, support members1158, 1160, and 1162 may be biased radially outwardly, and movablemembers 1152, 1154, and 1156 may urge support members 1158, 1160, and1162 into the retracted and contracted state. Sheath 1104 and supportmembers 1158, 1160, and 1162 may be moved proximally relative to movablemembers 1152, 1154, and 1156 to extend end effector 1106, allowing endeffector 1106 to move to its extended state.

As best shown in the exploded view in FIG. 12, the first actuator oractuation member 1108 may have a protrusion 1109 on its upper surface,on which the user may exert forces using his or her thumb to move thefirst actuator 1108 proximally to transition the end effector 1106 to afully open or partially open state and distally to a fully retracted,partially retracted, or a further retracted state. The first actuator1108 may have a generally “U” shape having a lumen therethrough, and maybe slidably disposed within the handle cover 1141 having a slot 1143through which the actuation member protrusion 1109 may extend. The firstactuator or actuation member 1108 also may include a stroke limiter 1128(FIG. 13). The stroke limiter 1128 may be a separated component such asa tube or may be formed on the first actuator 1108. The handle cover1141 may have various surface features to help the user hold the device1100.

A locator body 1146 may be disposed in a portion of the first actuator1108 lumen and may be operatively coupled to or formed within the handlebody 1140. The locator body 1146 may have one or more protrusions orstops for controlling the longitudinal movement of the first actuator1108. For example, the locator body 1146 may limit the sliding distanceof the first actuator 1108 by a distal stop 1126 or proximal stop 1147.The first actuator 1108 may include a distal face 1144 to operativelycouple to portions of the trigger assembly 1110. For example, FIG. 17shows a front view of the first actuator 1108 having a keyed front hole1150 to receive the trigger assembly 1110.

The proximal end of the locator body 1146 may include a vise 1122 or anyother suitable holding mechanism for holding drive member 1142. Whenvise 1122 closes, drive member 1142 may be fixedly coupled. An end cap1124 may be placed onto the proximal end of the handle assembly 1102 inany suitable manner (e.g. fasteners, adhesive, molding) to helpclose/clamp the vise around drive member 1142. For example, the handleassembly 1102 may include an externally threaded portion (not shown),and end cap 1124 may include complementary internal threading (notshown), so that end cap 1124 may be screwed onto handle assembly 1102.

The exterior surfaces of the locator body 1146 may have any suitablesize and shape and may correspond for disposal into lumen of the firstactuator 1108 having corresponding slots or grooves.

The trigger assembly 1110 may be fixedly coupled to a proximal portionof the sheath 1104 in any suitable manner, such as fasteners, snapfasteners, insert molding, heat shrink, adhesive, weld, etc. Forexample, the plunger 1114 may be insert molded on the sheath 1104. Thetrigger assembly 1110 may be operatively coupled to the first actuator1108 in any suitable manner. For example, as shown in FIGS. 12-16, thetrigger assembly 1110 may include flexing tabs or flexing tabs 1120,which may engage an interior surface of the first actuator 1108. Theflexing tabs 1120 may be formed on the outer surface of the plunger 1114and may snap into corresponding slots. In other embodiments, the flexingtabs 1120 may be replaced by keyed tabs, fasteners, screws, or any othersuitable couplings that allow limited two-way movement of the plunger1114 relative to first actuator 1108. The drive member 1142 may extendproximally through the sheath 1104 and a lumen of the trigger assembly1110, and the lumen 150 in the first actuator 1108, and may beoperatively coupled to the handle assembly 1102 at vise 1122.

In some embodiments, the trigger assembly 1110 may be operativelycoupled to the first actuator 1108 by a set screw and slot coupling (notshown). In this embodiment, one or more screw holes may be formed in adistal portion of the first actuator 1108, and a portion of the plunger1114 may include matching slots for each screw hole. Screws may bethreaded into the screw holes to be aligned and extended into the slotsin the plunger 1114. The screw may limit the sliding distance of theplunger 1114. The limit of longitudinal movement of the plunger 1114 maybe limited to the abutment of the screw to each end of the slot in theplunger 1114.

The biasing member 1116, such as a spring, may be disposed over aportion of the shaft 1112 of the trigger assembly 1110. The trigger 1118of the trigger assembly 1110 may extend from the plunger 1114. A usermay exert forces on the trigger 1118 of the trigger assembly 1110 usinghis or her thumb or index finger. Any suitable materials or combinationof materials having any suitable properties may be used to form thecomponents of the handle assembly 1102. For example, metals or polymers.The plunger 1114 and shaft 1112 may have any suitable size and shape.For example, the plunger 1114 may have flat, planar exterior surfacesfor keyed coupling with the first actuator 1108, and the shaft 1112 mayhave a round tubular shape over which biasing member 1116, such as aspring, may be disposed.

FIG. 12 shows partially unassembled portions of device 1100 in which cap1124 may be used to join the handle cover 1141, the drive member 1142,and locator body 1146 together. To assemble, the drive member 1142 maybe placed and located between portions of the vise 1122. The handlecover 1141 may be slid over the internal parts (e.g. first actuator 1108and locator body 1146) of the handle assembly 1102. The cap 1124 whentightened onto the handle cover and about the vise 1122, may compressthe vise 1122, locking the drive member 1142, locator body 1146, handlecover 1141, and cap 1124 together allowing the first actuator 1108 toslide relative to the locator body 1146.

As noted above, the internal components of the handle assembly 1102 maybe assembled by inserting the stroke limiter 1128 of a particular lengthfor a particular size end effector 1106 in the first actuator 1108. Thestop 1126 of the locator body 1146 may be aligned with the firstactuator 1108 and the locator body 1146 may be disposed into the firstactuator 1108. Prior to insertion into the handle body 1140, the plunger1114 may be fixed to the sheath 1104 in any suitable manner, forexample, insert molded, or glued. The biasing member 1116 may bepositioned on to the shaft 1112 of the trigger assembly 1110, and thetrigger assembly may be inserted into the keyed front hole 1150 of thefirst actuator 1108. The keyed hole 1150 may have any suitable shape andsize that may limit rotational movement of the plunger 1114 about thefirst actuator 1108 and to allow torque transfer from the handleassembly 1102 to the sheath 1104. The plunger 1114 may have a shape thatcorresponds to the keyed front hole 1150 of the first actuator 1108. Theshaft 1112 may be inserted and aligned through the front keyed hole 1150and extended through a mid-hole 1130 of the first actuator 1108, asshown in FIG. 13. The drive member 1142 may be disposed in the vise1122. The flexing tabs 1120 may be aligned to the keyed front hole 1150and may snap into place. The drive member 1142 may be trimmed to asuitable length so that the cap 1124 can be assembled at final assemblyof the device 1100.

The plunger 1114 may move a distance shown in FIG. 13 and FIG. 14. Theuser may use his or her thumb to move the plunger 1114 in one directionvia the trigger 1118 and the biasing member 1116 may return the plunger1114 back in the opposite direction. As the sheath 1104 is directlyfixed to the plunger 1114, changing the length of the plunger 1114relative to the first actuator 1108 moves the length of the sheath 1104relative to the first actuator 1108, which in turn moves the endeffector 1106.

As described above, the device 1100 may be used to retrieve a targetobject, such as organic material (e.g., blood clots, tissue, andbiological concretions such as urinary, biliary, and pancreatic stones)and inorganic material (e.g., components of a medical device or otherforeign matter), which may obstruct or otherwise be present within apatient's body cavities or passages. The device 1100 may be used forsingle hand use while the other hand may be used to manipulate anotherportion of the device 1100 or another device, such as an ureterscope. Inthis manner, using the trigger 1118 and the first actuator 1108, theuser may manipulate and maneuver both the device 1100 and any otherdevice (e.g. a scope) without the aid of an assistant. The user may usethe two actuators—the first actuator or actuation member 1108 and thesecond actuator or trigger assembly 1110 to manipulate the retractionand/or extension of the sheath 1104 relative to the movable members1152, 1154, and 1156 to open and close the end effector 1106.

As shown in FIG. 10 the end effector 1106 may be extended or opened tocapture the target object 1300. In order to accomplish this, theactuation member protrusion 1109 may be gripped and the first actuator1108 may be moved proximally relative to the handle body 1140 and thedrive member 1142 along the locator body 1146 and shaft 1112. In anextended or open state as shown in FIG. 13, a proximal end of the firstactuator 1108 may abut with a proximal protrusion of the locator body1146. As first actuator 1108 moves proximally, the sheath 1104 maywithdraw proximally to expose the movable members 1152, 1154, and 1156allowing the end effector 1106 to expand or open. This proximal movementis accomplished by the abutting connection of the proximal end of theplunger 1114 to the first actuator 1108 by flexing tabs 1120, and theconnection of the distal end of the plunger 1114 to the sheath 1104.

As shown in FIG. 14, the trigger assembly 1110 may be used to furtherextend or open the end effector 1106. The trigger 1118 may be actuatedto move the trigger assembly 1110 in the proximal direction. The trigger1118 may be operated with the index finger or the thumb to pull thetrigger 1118 proximally. Proximal movement of the trigger 1118 maycompress the biasing member 1116 and further withdraw the sheath 1104proximally an additional distance to further extend or open the endeffector 1106 beyond its normal operating range (diameter) for thepurposes of capturing a larger target through its front opening,releasing a stuck target object, or to enlarge the side opening of theend effector 1106 to allow larger side opening target object capture.Upon release of the trigger 1118, the biasing member 1116 may return theplunger 1114 back to its original stroke length (FIG. 13). The change inthe length of the biasing member 1116 may be equal to the movement ofthe sheath 1104 relative to the first actuator 1108.

FIG. 15 shows the end effector 1106 in a standard or fully closed orretracted state. The retracted state may be accomplished by moving thefirst actuator 1108 distally a distance having a stroke length “S”starting at a position S1 (corresponding to a distal end of the strokelimiter 1128) and moving to a position near stop 1126. The actuationmember protrusion 1109 may be gripped and the first actuator 1108 may bemoved distally relative to the handle body 1140 and the drive member1142 along the locator body 1146 and shaft 1112. In a retracted state asshown in FIG. 15, the sheath 1104 may be urged over the movable members1152, 1154, and 1156 to retract the end effector 1106.

FIG. 16 shows the end effector in a further retracted state in which thefirst actuator 1108 may be further pushed in a distal direction anadditional stroke length “A” for a total stroke length “T” from thefully retracted state shown in FIG. 15 at which the stroke limiter 1128travel from position S1 to a position abutting stop 1126 to maintainretraction of the end effector 1106. This state may be advantageous, forexample, when the device 1100 is traversing a tortuous path in the body,and the end effector 1106 may require the assistance of the biasingmember 1116 to maintain the end effector 1106 in a closed or retractedstate. In this further retracted state, the standard stroke length “S”may be increased by an additional “A” closure length. The additionalclosure length “A” may assure sufficient sheath 1104 length to slideover the end effector 1106 and may provide tactile confirmation that theend effector 1106 is fully retracted. Any movement of 108 beyond themaximum distal movement of sheath 1104 (as defined by the movablemembers limiting movement of the support members distally), may resultin displacement of the biasing member 1116 to cause the biasing member1116 to compress. In turn, the compression of the biasing member 1116controls the stresses at the end effector 1106 in the closed position,in that the spring force replaces the force applied to the firstactuator or actuation member 1108. As the first actuator 1108 isreleased, the biasing member 1116 may return the flexing tabs 1120 backto the back side of the first actuator 1108, and the sheath 1104 to anextended length as shown in FIG. 15. Thus, the biasing member 1116allows for a lost motion connection between the first actuator 1108 andthe second actuator 116. In addition, the first actuator 1108 maytransfer a force to the biasing member 1116 when the first actuator 1108moves in the distal direction. The biasing member 1116 is configured toreduce the force, and transfer the reduced force to the sheath 1104,when the force on the first actuator 1108 exceeds a predetermined value.As the first actuator 1108 moves distally relative to the handle body1140, the additional distance A beyond the first distance S, the biasingmember 1116 compresses as the first actuator 1108 moves the additionaldistance A.

For example, as the sheath 1104 is restricted from moving in the distaldirection by the bends of the movable member 1152, 1154, and 1156 forclosure, the continued movement of the first actuator 1108 in the distaldirection compresses the biasing member 1116 a predetermined distance“x” against the plunger 1114. The force that the compressed biasingmember 1116 exerts on the plunger 1114 which, is connected directly tothe sheath 1104 is in accordance with Hooke's law F=Kx discussed above,where K is the spring constant and x is equal to the additional distanceA shown in FIG. 15. Since the biasing member 1116 is compressedinitially during the assembly of the plunger 1114 to the first actuator1108, F=Kx, where x=A+x, where x₁=the free length of the biasing member1116−the initial compressed length of the biasing member 1116. The forceexerted by the biasing member 1116 on the sheath 1104 and support tubes1158, 1160, and 1162 at the end of stroke distance A is greater than thestroke distance S, since the change of the length of the biasing member1116 is greater at the end of stroke A. At the end of stroke S, thebiasing member 1116 may be biasing the plunger 1114 against the firstactuator 1108, thus and no spring force may be exerted to the sheath1104. The closed or retracted state shown in FIG. 15 in which the firstactuator 1108 moves a stroke distance S to completely close the endeffector 1106 and further movement of the first actuator 1108 theadditional stroke distance A may provide an additional closure force.

The biasing member 1116 may have any suitable properties according toHooke's law. For example, the biasing member 1116 may have any suitablespring constant K, such as between 0.700 lb./in and 0.900 lb./in. Insome embodiments, the biasing member 1116 may have a K value of about0.872 lb./in. The biasing member 1116 may have any suitable load height,for example, an initial load height of about 1.130″ producing an initialspring force of about 0.104 lbf (0.047 kgf). The biasing member 1116 mayhave any suitable expansion force such as no more than about 0.7 lbf(0.32 kgf) when the biasing member 1116 is compressed about 18 mm toforce the plunger 1114 to extend distally and to return the length ofthe sheath 1104 to its initial length. A force of about 0.25 lbf (0.11kgf) may be of sufficient force to advance the sheath 1104 over thedrive member 1142 further compressing the biasing member 1116 to advancethe sheath 1104 to close the end effector 1106 when the first actuator1108 is moved in the distal direction. In one embodiment, the size ofthe end effector 1106 may be between 30 to about 70% larger in therelease state shown in FIG. 14 than in the extended state shown in FIG.13. For example, the maximum standard open size of the end effector 1106in the extended state (FIG. 13) may be about 8 mm in diameter and thetrigger assembly 1110 may further extend the open size to about 15 mm inthe release state (FIG. 14). The biasing member 1116 provides a neutralbias to the first actuator 1108 when the end effector 1106 is in theextended state shown in FIG. 13.

The device 1100 also may provide stroke relief when the device isactuated. For example, distal movement of sheath 1104 coupled to theplunger 1114 may be restricted when the device is in the closed orretracted position with the end effector 1106 is empty, or when the endeffector 1106 is holding an object. Movement of the first actuator 1108in the distal direction when the sheath is retracted will compress thebiasing member 1116 a predetermined distance against the plunger 1114.The force that the compressed biasing member 1116 exerts on the plunger1114, which is fixed to the sheath 1104 is F=Kx (Hooke's law), where Kis the spring constant and x is equal to the change in the length of thebiasing member 1116 delta x, since the biasing member 1116 may beinitially compressed during assembly of the plunger 1114 to the firstactuator 1108. Then F=Kx where x equal delta x+x₁ where x₁=(free lengthof the biasing member 1116)−(the initial compressed length of thebiasing member 1116). The force exerted by the compressed biasing member1116 on the sheath 1104 and support tubes 1158, 1160, and 1162 may beless than the force applied directly by the first actuator 1108 if thebiasing member 1116 were not present, thus relieving or controlling thestroke force. The biasing member 1116 may have any suitable K constant.

In one embodiment, a target object may be captured by opening the endeffector 1106 to its open diameter in the extended state (FIG. 13) andadvancing the front opening of the end effector 1106 towards the targetobject, capturing the object, moving the target object to a desiredlocation. Actuating trigger assembly 1110 may be moved proximally tofurther open the end effector 1106 to the further extended or releasestate (FIG. 14), to grab or capture larger target objects. The triggerassembly 1110 also may be advantageously used to open the end effector1106 during release of the object so that the end effector 1106 may opento a larger size than the end effector 1106 during capture of the targetobject. Thus, the trigger assembly 1110 may be activated when therelease state is needed or when a target object is stuck in the effector1106.

Additionally or alternatively, and referring to FIGS. 9-17, the biasingmember 1116, when assembled in handle assembly 1102, may be compressedbetween the plunger 1114 and a portion of the first actuator 1108. Forexample, the biasing member 1116 may be compressed between the plunger1114 and a rib, wall, or protrusion on an underside of the firstactuator 1108 (FIGS. 13-16). The biasing member 1116 may be compressedto an initial length from an equilibrium length to bias the firstactuator 1108 relative to the sheath 1104 with a restoring force. Thebiasing member 1116, when not compressed or tensioned, may be in itsequilibrium length, where a change in length of the biasing member 1116is near or equal to zero, resulting in the restoring force exerted bythe biasing member 1116 to be near or equal to zero. The compressedinitial length of the biasing member 1116, however, may exert arestoring force on a proximal end portion of the plunger 1114 and/or therib of the first actuator 1108, thereby extending and maintaining thesheath 1104 in a position, with portions of the sheath 1104 at adistance from the first actuator 1108, during operation of the endeffector 1106.

The initial restoring force may correspond to the compressed initiallength, and may be calculated using Hooke's law. For example, theinitial restoring force “F” exerted on the sheath 1104 and supportmembers 1158, 1160, and 1162 by the biasing member 1116, when thebiasing member 1116 is at its compressed initial length, can becalculated using the equation F₁=−kx₀₁, where F₁ is a resulting forcevector (e.g., a magnitude and direction of the restoring force thebiasing member 1116 exerts on the sheath 1104 via the plunger 1114 andalso is the restoring force the biasing member 1116 exerts on the firstactuator 1108); k is a rate, spring constant, or force constant of thebiasing member 1116, which may depend on material and construction ofbiasing member 1116; the negative sign may indicate that the force thebiasing member 1116 exerts is in a direction opposite from itsdisplacement; and x₀₁ is a displacement vector (e.g., a distance anddirection the biasing member 1116 may be deformed from its equilibriumlength or free length to its initial length).

Referring to FIGS. 9-11, the sheath 1104 and attached support members1158, 1160, and 1162 may retract relative to the drive member 1142 whenthe initial restoring force exerted by the biasing member 1116 isovercome by another force, such as friction or drag. Put another way,the initial restoring force may be used to maintain a substantiallyconstant working length of the sheath 1104 relative to the firstactuator 1108. In turn, the support members 1158, 1160, and 1162 maycover and/or retract a consistent length relative to the movable members1152, 1154, and 1156 to fully close the end effector 1106 and/or tofully open the end effector 1106 to a consistent size.

The size of the end effector 1106 may be expressed in terms of lengthsof the movable members 1152, 1154, and 1156 that may be extended andretracted from the tips of the support members 1158, 1160, and 1162 toform a perimeter of the distal loop of the end effector 1106. Thelengths or amounts of the movable members 1152, 1154, and 1156 extendedfrom the end of each of the support members 1158, 1160, and 1162 may begoverned by the stroke length of the first actuator 1108, and/or may beequated to a maximum stone dimension or that can fit in the perimeter ofthe front loop of the end effector 1106.

The initial restoring force at the initial length of the biasing member1116 may be selected so as to be greater than a friction force that maybe encountered between the assembly of the movable members 1152, 1154,and 1156 and the drive member 1142, and the assembly of the sheath 1104and the support members 1158, 1160, and 1162 when they are operated in atortuous path. This initial restoring force setting may enable thesheath 1104 to maintain its working length, and overcome drag to enablethe end effector 1106 to fully expand, extend, contract, and/or retract.

As stated above, the initial restoring force may maintain the workinglength of the sheath 1104 during expansion and contraction of the endeffector 1106, brought about by proximal and distal strokes of the firstactuator 1108, when there is no stone present. The same strokes of thefirst actuator 1108 may be used to capture a stone. The maximum stressand strain applied to components of the retrieval device 1100 by therestoring force of the biasing member 1116, may occur after a distalstroke of the first actuator 1108 that puts the end effector 1106 in afully contracted and retracted state.

The amount of stress and strain that may be applied to the components ofthe retrieval device 1100 may be limited or otherwise managed. This maybe accomplished using the biasing member 1116, which may include a coilspring, by selecting or setting a maximum restoring force of the biasingmember 1116. For example, the maximum restoring force may be below thematerial strength of components of retrieval device 1100 that can bedamaged during a distal stroke of the first actuator 1108.

The maximum restoring force generated by a user's hand may be a functionof the maximum stone size that can be captured in the front loop of theend effector 1106. A stone's perimeter may be used to approximate thestone's cross-section that is captured by the front loop. Limiting thesize of the front loop, more specifically the perimeter of the frontloop that is formed when the end effector 1106 is in the expanded state,will limit the size of stone that can be captured only to those stoneswith an equal to or smaller perimeter than the front loop. By limitingthe maximum stone size that can be captured, the maximum restoring forcethat can be applied by the restoring force of the biasing member 1116 tothe components of the retrieval device 1100 may be limited.

When capturing a stone, one scenario may involve the user opening theend effector 1106 to its maximum front loop perimeter with the firstactuator 1108, by sliding the first actuator 1108 with a full proximalstroke, whereby the end effector 1106 may be fully expanded and extended(FIG. 13). The user may position and engage the front loop perimeterover the perimeter of the stone to be captured. The user may then startto slide the first actuator 1108 in the distal direction with a distalstroke, causing the end effector 1106 to move to its contracted andretracted state, and closing the end effector 1106 about the stone. At apoint of the distal stroke, the stone's perimeter may begin to preventthe front loop from closing all the way to a fully contracted state.This may cause resistance between the assembly of the sheath 1104 andsupport members 1158, 1160, and 1162, and the assembly of the movablemembers 1152, 1154, and 1156 and the drive member 1142, preventing thesupport members 1158, 1160, and 1162 from sliding over the movablemembers 1152, 1154, and 1156. When the resistance force becomes equal toor greater than the initial restoring force F₁ at the initial length ofbiasing member 1116, further sliding of the first actuator 1108 in thedistal direction may start to compress the biasing member 1116 to aloaded length (FIG. 14), increasing its restoring force, and tighteningthe front loop about the stone. The maximum restoring force and themaximum tightness of the front loop about the stone, may be reached atthe end of the distal stroke of the first actuator 1108.

The maximum stress and strain applied to one or more of the componentsof the retrieval device 1100, such as to the support members 1158, 1160,and 1162, sheath 1104, movable members 1152, 1154, and 1156, and/ordrive member 1142, may occur when the first actuator 1108 is actuatedwith a distal stroke to its position that corresponds to the endeffector 1106 being fully contracted and retracted, with a stone ofmaximum size captured within the end effector 1106 front loop. Thismaximum restoring force may also be the maximum force that the hand mayapply via the first actuator 1108. Put another way, the hand may apply aforce via the first actuator 1108 substantially equal to the restoringforce of the biasing member 1116, the magnitude of the restoring forcebeing a function of the size of the stone's perimeter that is engagedwith the front loop of the end effector 1106. It should be noted thatthe restoring force acting on the sheath 1104 and the end of the plunger1114 may also be the restoring force of the biasing member 1116 that isacting on the first actuator 1108.

A change in the length (X₀₂) of the biasing member 1116 when the biasingmember 1116 is placed under a load, or the change in the compression ofthe biasing member 1116 from the equilibrium length when placed under aload, may be a function of the size of the stone being capture, and morespecifically, a function of the size of the perimeter of the stone aboutwhich the front loop of the end effector 1106 conforms and tightens.Initial closure of the end effector 1106 by the advancement of the firstactuator 1108 may close the front loop about the surface of the stone.The perimeter of the stone is approximated by the perimeter of the frontloop. Further closure of the end effector 1106 against the stone by theadvancement of the first actuator 1108 may cause sufficient resistanceof the support members 1158, 1160, and 1162 from advancing over one ormore exposed portions of movable members 1152, 1154, and 1156, causingthe biasing member 1116 to compress or change its length. The change inlength (X₀₂) may be approximately ⅓ of the perimeter of the stone thatis captured by or within the front loop, since there are three movablemembers 1152, 1154, and 1156 that extend equally to form the front loop.

For the simplicity of perimeter calculations described below, a stonehaving a circular cross section (e.g., a spherical or cylindrical stone)is used. The change in length X₀₂ can be approximated by thecircumference of the stone divided by 3, or (*d)/3, where d is adiameter of the stone. However, one of ordinary skill would appreciatethat stones may have irregular shapes, and that the calculationsdescribed herein may be adjusted based on the particular stone shape.

A restoring force “F” may be exerted on the components of retrievaldevice 1100, such as the sheath 1104 and/or support members 1158, 1160,and 1162 by the biasing member 1116 as the first actuator 1108 is moved.F₂ may also be the force that is exerted on the first actuator 1108 bythe biasing member 1116. The restoring force “F” may be the same inmagnitude for two different stones when the stones' perimeters are equalon length.

The restoring force F can be calculated using Hooke's Law, whereF=−KX₀₂, wherein: F=the resulting force vector—the magnitude anddirection of the restoring force the biasing member 1116 exerts on thesheath 1104 via the plunger 1114 with distal movement of the firstactuator 1108, and also the restoring force the biasing member 1116exerts on the first actuator 1108; K=the rate, spring constant, or forceconstant of the biasing member 1116, a constant that depends on thebiasing member's material and construction, wherein the negative signindicates that the force the biasing member 1116 exerts is in theopposite direction from its displacement; X₀₂=the displacementvector—the distance and direction the biasing member 1116 is deformedfrom its equilibrium length or free length to its loaded length withmovement of the first actuator 1108 in the distal direction.

Additionally or alternatively, the restoring force “F” can also becalculated in terms of the initial restoring force F, wherein F=F+(k*X),where: F₁=the Initial restoring force at initial load length; and X=adisplacement vector—the distance and direction the biasing member 1116is deformed from its initial length to its loaded length during movementof the first actuator 1108.

When opening (e.g., expanding and extending) the end effector 1106, thefirst actuator 1108 may be pulled in a proximal direction to withdrawthe sheath 1104 and the support members 1158, 1160, and 1162 from themovable members 1152, 1154, and 1156 (FIGS. 9, 10, and 13). In movingthe first actuator 1108 in the proximal direction, the first actuator1108 may engage the plunger 1114 directly by flexible tabs 1120 towithdraw the attached sheath 1104 and the support members 1158, 1160,and 1162 from the movable members 1152, 1154, and 1156. The biasingmember 1116 may have little to no influence during the withdrawal,except that the initial restoring force F may retain the first actuator1108 and plunger 1114 a set distance apart by biasing the flexible tabs1120 against an inner wall of the first actuator 1108.

The end effector 1106 may be in an expanded and extended state whenfirst actuator 1108 has been moved a full stroke in the proximaldirection (FIGS. 9, 10, and 13). The front loop of the end effector 1106can be extended even further to create a larger front loop by pullingthe trigger 1118 with the thumb or index finger in the proximaldirection to withdraw the sheath 1104 even further and to compress thebiasing member 1116 at the same time (FIG. 14). The larger opened frontloop may allow stuck stones to be released or enable larger stones to becaptured. The restoring force of the compressed biasing member 1116 mayreturn the plunger 1114, sheath 1104, support members 1158, 1160, and1162, and front loop of the end effector 1106 back to its state prior toactuation of the trigger 1118 when the trigger 1118 is released. Therestoring force applied to the plunger 1114 by the biasing member 1116may be determined by Hooke's law.

When closing the end effector 1116 without a stone present, the firstactuator 1108 may be pushed in the distal direction to advance thesheath 1104 and support members 1158, 1160, and 1162 over the movablemembers 1152, 1154, and 1156 (FIGS. 11 and 15). If the initial restoringforce F (from the initial compression of the biasing member 1116) is notsufficient to push the sheath 1104 and support members 1158, 1160, and1162 over the movable members 1152, 1154, and 1156, due to, for example,friction between the sheath 1104 and the drive member 1142 and/or themovable members 1152, 1154, and 1156, and/or between the support members1158, 1160, and 1162 and the movable members 1152, 1154, and 1156, dueto the components traversing a tortuous path, the initial restoringforce may be adjusted to a higher magnitude by, for example, replacingthe biasing member 1116 with another biasing member having differentproperties that produce a greater initial restoring force.

To determine an approximate restoring force exerted on the sheath 1104by the biasing member 1116 (and other biasing members), F, or the changein load height from X to X (X), parameters may be measured directly fromthe handle assembly 1102. More specifically, X may be the change in thelength of the biasing member 1116 from its initial length to its loadedlength, and can be measured by the change in plunger length or by theamount of plunger length that is retracted into the first actuator 1108.X can also be calculated by subtracting the remaining exposed plungerlength from its initial exposed plunger length.

The retrieval device 1100 may control the grip force of the front loopof the end effector 1116 as a function of the stone size. The endeffector 1106 may operate by reciprocal motion of the sheath 1104 andsupport members 1158, 1160, and 1162 relative to the drive member 1142and movable members 1152, 1154, and 1156. The movable members 1152,1154, and 1156 may be weaved in and out of the support members 1158,1160, and 1162 to form the end effector 1106 (see FIG. 10). Ends of themovable members 1152, 1154, and 1156 that are not attached to the drivemember 1142 may terminate at a coupler (shown but not numbered in FIG.11), such as the coupler 140. The end effector 1106 may be opened andclosed by withdrawing or advancing the sheath 1104 and support members1158, 1160, and 1162, by the use of the first actuator 1108, relative tothe drive member 1142 and movable members 1152, 1154, and 1156. Themagnitude of the restoring force that is exerted by the biasing member1116 may be affected by the size of the stone, and more specifically,the perimeter of the stone that is capture by the front loop of the endeffector 1106. Stones of the same perimeter size may generate the samerestoring force when captured through movement of the first actuator1108. A large stone with a large perimeter may generate a restoringforce greater than a small stone with a small perimeter when captured,when the first actuator 1108 is actuated.

Referring to FIGS. 13-16, the restoring force of the biasing member 1116may act on both ends of the biasing member 1116. On one end, therestoring force may be applied directly to the first actuator 1108,while the restoring force at the other end of the biasing member may beapplied to the plunger 1114 (and to sheath 1104). The sheath 1104 maybranch off to support members 1158, 1160, and 1162, and so may therestoring force. The restoring force may be equally distributed to eachof the support members 1158, 1160, and 1162. Put another way, for eachof the support members 1158, 1160, and 1162, the force applied may beequal to the restoring force divided by the number of support members.The two movable members within each of the support members 1158, 1160,and 1162 may be subjected to the restoring force acting on supportmembers 1158, 1160, and 1162. The portion of the restoring forcedistributed to each of the support members 1158, 1160, and 1162 maybranch off to the movable members 1152, 1154, and 1156 extending fromthat support member. For example, when there are two movable membersextending from a support member, the force on each movable member may beequal to half of the portion of the restoring force on the supportmember. A gripping force of the front loop may be the sum of all theforces on the movable members 1152, 1154, and 1156, which may equal therestoring force of the biasing member 1116. The restoring force of thebiasing member 1116, at full stroke of the first actuator 1108, may bedependent upon stone size. The maximum grip force that can be applied bythe retrieval device 1100 may therefore be dependent on the maximumstone size that can fit into the perimeter of the front loop during afull closing stroke of the first actuator 1108.

Each of the support members 1158, 1160, and 1162 may act as a coupler tohold two of movable members 1152, 1154, and 1156 together to form thefront loop. The gripping force of the front loop may be distributedevenly about the front loop when capturing a stone, such that each ofthe support members 1158, 1160, and 1162 and each of the movable members1152, 1154, and 1156 may be subjected to the gripping force of the frontloop. A minimum tear strength requirement for the support members 1158,1160, and 1162 should be set above the maximum grip force of the frontloop, and/or above the restoring force of the biasing member 1116 whenthe front loop captures the maximum stone size allowed and the firstactuator 1108 undergoes a full closing stroke.

FIGS. 18 and 19 show another embodiment of a medical retrieval device1800 similar to medical retrieval device 1100 in which second actuatorin the form of a trigger assembly 1810 is external from and handleassembly 1802. Trigger assembly 1810 may include a biasing member 1816,a biasing member housing 1860 for housing the biasing member 1816 in theform of a spring, a piston body 1862, and a trigger 1818 extending fromthe biasing member housing 1860. The distal end of the biasing memberhousing 1860 may be fixed to the outer surface of the sheath 1804 in anysuitable manner, such as by glue, heat shrink, etc. In one aspect, thepiston body 1862 may include a snap trigger members (not shown) that arerecessed in opposing internal slots (not shown) in the biasing memberhousing 1860. The proximal end of the biasing member housing 1860 may becoupled to a portion of the piston body 1862 in any suitable manner,such as via latches, fasteners, etc. The proximal end of the piston body1862 may be attached to the distal end of the actuation member 1808 ofthe handle assembly 1802 in any suitable manner, such as by threads,interference fit, glue etc. Alternatively, the actuation member 1808 andthe piston body 1862 may be formed as a single part.

The piston body 1862 may include a distal portion 1866 of a first widthor diameter and a proximal portion 1868 of a second width or diameter.The distal portion 1866 slides within a distal reduced opening in thebiasing member housing 1860 and the proximal portion 1868 of the pistonbody 1860 is received in a larger opening of the biasing member housing1860. The distal portion 1866 of the piston body 1862 includes an endface that abuts a proximal end of biasing member 1816.

The trigger assembly 1810 may be actuated to transition the device fromthe extended state shown in in FIG. 18 to the further extended stateshown in FIG. 19 by moving the trigger 1818 in a proximal directionalong piston body 1862 towards the actuation member 1808 to compress thebiasing member 1816, in turn withdraw the sheath 1804, and supportmembers. Actuation of the trigger assembly 1810 moves the sheath 1804 anadditional distance to further extend or open the end effector 1806beyond its normal operating range (diameter) for the purposes ofcapturing a larger target objects through its front opening, releasing astuck target object, or to enlarge the side opening of the end effector1806 to allow larger side opening target object capture. Upon release ofthe trigger 1818, the biasing member 1816 may return the biasing memberhousing 1860 back to its original stroke length shown in FIG. 18. Thechange in the length of the biasing member 1816 may be equal to thechange in the length of the sheath member 1804 relative to the actuationmember 1808. In some embodiments, the biasing member housing 1860 mayinclude relief slots extending therethrough, which may allow portions ofthe biasing member housing 1860 to expand in various directions. Forexample, two relief slots may extend along a top portion and two reliefslots may extend along a bottom portion of the biasing member housing1860. The biasing member housing 1860 also may include a flexing tab orramp portion at a proximal end for engaging a corresponding slot oropening on the piston body 1862 and/or a slot for engaging a ramp.

The disclosed retrieval devices may be utilized in any suitableapplication involving the capture and removal of materials from thebody. Any aspect set forth herein may be used with any other aspect setforth herein. The devices may be used in any suitable medical procedure,may be advanced through any suitable body lumen and body cavity, and maybe used to remove material from any suitable body portion. For example,the devices described herein may be used through any natural body lumenor tract, including those accessed orally, vaginally, rectally, nasally,urethrally, or through incisions in any suitable tissue.

The disclosed devices may be configured to capture fragments havingdimensions of about 5 French or smaller. In some arrangements, thedisclosed medical devices may be able to capture and release stoneshaving diameters from 1 millimeter to 20 millimeters. In somearrangements, a user may want to reposition larger stones from the lowercalyx to the upper calyx of the kidney to be broken with a laser beforeremoving them through a small diameter of the ureter. The stones may beremoved in front of a scope, as opposed to through scope channel toprevent damage to a scope channel. When stones are removed, both anendoscope and the retrieval device may be removed from the human body.In some arrangements, a guide sheath for a ureteroscope may be used toguide the ureteroscope and retrieval device back to a previous positionor to a new position to capture additional stones, and protect a ureterwall during stone removal. While moving from the extended and expandedstate to the retracted and contracted state, retrieval devices of thepresent disclosure may ligate larger stones and capture smaller stoneswithin their end effectors.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the disclosed systems andprocesses without departing from the scope of the disclosure. Variousaspects of the disclosed devices and processes may be used together inany suitable combination, or used separately. Other aspects of thedisclosure will be apparent to those skilled in the art fromconsideration of the specification and practice of the featuresdisclosed herein. It is intended that the specification and examples beconsidered as exemplary only.

1.-20. (canceled)
 21. A method for operating a device including asheath, an end effector, and a handle assembly, the method comprising:actuating an actuation member on the handle assembly in a firstdirection to transition the end effector from a retracted state to anextended state, the end effector being at the distal end of the sheath,and the end effector including a support member extending from thedistal end of the sheath, and a movable member extending from the distalend of the support member; actuating a trigger member on the handleassembly to transition the end effector from the extended state to afurther extended state, wherein in the further extended state, the endeffector is extended or opened a greater amount than in the extendedstate; actuating the actuation member in a second direction opposite tothe first direction to transition the end effector to the retractedstate; and further actuating the actuation member in the seconddirection to transition the end effector to a further retracted state.22. The method of claim 21, wherein extending or retracting the endeffector includes moving one of the movable member and the supportmember relative to the other of the movable member and the supportmember, and wherein the relative movement of the movable member and thesupport member is biased by a biasing member coupled to at least one ofthe actuation member and the sheath.
 23. The method of claim 22, whereinthe biasing member moves from the biasing state to the rest state totransition the end effector to the retracted state with a predeterminedforce.
 24. The method of claim 22, wherein the biasing member includes aproximal end fixedly coupled to the sheath, and wherein the biasingmember includes a distal end movable relative to the sheath.
 25. Themethod of claim 21, wherein actuating the actuation member on the handleassembly includes sliding the actuation member relative to the handleassembly.
 26. The method of claim 21, wherein the end effector includesa plurality of support members fixedly coupled to the distal end of thesheath, and a plurality of movable members extending through the supportmembers and movable between the extended state, the further extendedstate, the retracted state, and the further retracted state.
 27. Themethod of claim 26, wherein the support members extend distally beyond adistal end of the sheath in the extended state, the further extendedstate, the retracted state, and the further retracted state.
 28. Themethod of claim 27, wherein the actuation member and the trigger memberare operable to move the movable members relative to the support membersfor transitioning the end effector between the extended state, thefurther extended state, the retracted state, and the further retractedstate.
 29. The method of claim 21, wherein the device further includes aconnector between the handle assembly and the proximal end of thesheath, and wherein the connector includes a port in fluid communicationwith a lumen of the sheath.
 30. The method of claim 21, furtherincluding capturing an object within the end effector when the endeffector is transitioned into the extended state, and securing theobject within the sheath when the end effector is transitioned into theretracted state.
 31. A method for operating a device including a sheath,an end effector, a handle assembly, and a biasing member, the methodcomprising: actuating a first actuator on the handle assembly totransition the end effector from an extended state to a retracted state,the end effector being at the distal end of the sheath, and the endeffector including a plurality of support members and a plurality ofmovable members extending from the distal end of the sheath, whereintransitioning the end effector from the extended state to the retractedstate includes relative movement between the plurality of supportmembers and the plurality of movable members; and actuating a secondactuator operatively coupled to the sheath to provide relative movementbetween the plurality of movable members and distal ends of theplurality of support members, wherein the biasing member is coupledbetween the first actuator and the second actuator, and wherein thebiasing member controls a force exerted on one of the movable membersand the support members by the other of the movable members and thesupport members.
 32. The method of claim 31, wherein the biasing memberis configured to deform to facilitate movement of the end effector fromat least one of the extended state to a further extended state, and theretracted state to a further retracted state.
 33. The method of claim31, wherein the biasing member provides a lost motion connection betweenthe first actuator and the second actuator.
 34. The method of claim 31,wherein the first actuator is configured to move in a distal directionrelative to a handle body to move the sheath and transition the endeffector to the retracted state.
 35. The method of claim 34, wherein thefirst actuator is configured to transfer a force to the biasing memberwhen the first actuator moves in the distal direction, and wherein thebiasing member is configured to deform due to the force when the forceon the first actuator exceeds a predetermined value.
 36. The method ofclaim 35, wherein the first actuator is configured to move in a proximaldirection relative to the handle body to move the sheath and transitionthe end effector to the extended state, and wherein the second actuatoris configured to transfer a force to deform the biasing member when thesecond actuator moves in the proximal direction.
 37. A device,comprising: a sheath including a distal end and a proximal end; an endeffector at the distal end of the sheath, the end effector including aplurality of support members and a plurality of movable membersextending from the support members, the end effector being movablebetween at least an extended state and a retracted state via relativemovement between the plurality of support members and the plurality ofmovable members; and a handle assembly including a first actuatoroperatively coupled to the sheath to provide relative movement betweenthe plurality of movable members and distal ends of the plurality ofsupport members, a second actuator operatively coupled to the sheath toprovide relative movement between the plurality of movable members anddistal ends of the plurality of support members; and a biasing memberoperatively coupled between the first actuator and the second actuator,the biasing member being configured to deform to facilitate movement ofthe end effector from at least one of the extended state to a furtherextended state, and the retracted state to a further retracted state,wherein the biasing member provides a lost motion connection between thefirst actuator and the second actuator.
 38. The device of claim 37,wherein the first actuator is configured to move in a distal directionrelative to a handle body to move the sheath and transition the endeffector to the retracted state.
 39. The device of claim 38, wherein thefirst actuator is configured to transfer a force to the biasing memberwhen the first actuator moves in the distal direction, and the biasingmember is configured to deform due to the force when the force on thefirst actuator exceeds a predetermined value.
 40. The device of claim37, wherein the first actuator is configured to move in a proximaldirection relative to the handle body to move the sheath and transitionthe end effector to the extended state, and the second actuator isconfigured to transfer a force to deform the biasing member when thesecond actuator moves in the proximal direction.